I apologize: I can’t remember if I responded to your first point in this reply.
But now I'm wondering: would you like to see changes in the sexual behaviour of people?
Well, of course. I think we are all sinners, there’s plenty of different sins, each person has a different hand of cards from the deck, and we all must strive to live as good (ethical) lives as possible. There is such a thing, in traditional thought, albeit non-existent in progressive thought (usually), as immoral sexual acts that are consensual between parties and acts against oneself.
By analogy, there was real world event where two men consented for
one of them to eat the other. If consenting—in a proper way free of duress and inhibitory conditions—eliminates the possibility of an act being harmful or, perhaps, simply is morally permissible in virtue of it being consensual; then there’s nothing wrong with what happened.
However, when we view ethics in a naturalistic way (metaethically), it becomes clear this is immoral because it deprives the one killed of their nature completely (by there non-existence) and so all ‘the good’ for them is lost and the action is contrary to every natural end of them—existence being the most fundamental good and prerequisite for all other goods. I would be interested to know what ethical theory you are operating under—metaethically, normative ethically, and applied ethically—to evaluate this example to compare.
If so, how should that be achieved?
I think socially we should have norms that incentivize the good and dis-incentivize the bad and of which cultivate a nation-soul centered around the virtues and human flourishing.
A key tenant of Christian thought is love of perfect goodness (God) and of the ordering of things relative to Him—to the point of loving your enemies and wanting their good even as they nail you to a cross. I think society legally and socially should reflect this. This is where the idea of responding to evil with only proportionate and without retaliation comes from: if you love your enemy, you seek not to destroy or annihilate them but to stop them from doing evil and to change their ways.
When you state that certain sexual behaviours are immoral, do you propose to do anything about it or would you like anyone else to do something about it?
The response to evil needs to be proportionate (out of love not for the evil but the person who mistakenly embodies it) and centered towards what is good for all (including the person committing the evil). Hence, justice proper is restorative and not retributive; and not all immoral acts deserve physical force to stop.
In cases of injustice (viz., immoral acts against a person), physical force as a means to enforcing morality is reserved for immoralities that are, in their gravity (either to the other person afflicted or an act against oneself), detrimental enough to the good of the victim that it is proportionate to do so. Proportionality is key here. E.g., a person that is inflicting themselves with self-hate (which causes them to be down in the weather a bit) is not something which would warrant physical force (because it would be disproportionate as a remedy to the situation); but if they are trying to commit suicide (even consensually and in a state where they are not ‘out of their mind’) then it is justified to use force to save them. E.g., stopping a murder by physical force is proportionate but stopping someone from being mean to someone else on purpose does not warrant such force.
Also, the penal system, applied ethically, is supposed to mimick providing a remedy to restore the dignity of the one offended and the will of the (repentant) criminal (although I grant this is not at all what happens in American prison systems at all). Consequently, self-inflicted sins require a different approach because the one offended and the offender are the same. In short, it wouldn’t make sense to imprison or criminally charge someone for doing evil against themselves; instead, it would require rehabilitation.
There’s also a practical aspect, applied ethically, to this too that cannot be ignored. I am weary of the government; and so I am not interested in trying to setup cameras everywhere like in China to stop people from doing every immoral deed. There has to be checks and balances here.
The question becomes: “where does homosexuality and transgenderism fall in terms of the gravity of the act?”.
In short, transgenderism would be viewed, in my view, as I’ve unapologetically said many times in this thread, as a mental illness and be treated like one. The context matters: sometimes a schizophrenic is posing too much of a risk to themselves and the public so they get sent to a rehab center; sometimes they are stable enough to live productive lives in society. I think if a transgender is posing a significant risk to themselves then, similarly, we have a duty to help them by protecting themselves from themselves and rehabilitate them. If they are not posing a significant risk and can live a productive life in society (which many can and do), then that shouldn’t happen. Where the analogy breaks, is that schizophrenia causes a risk by way of hallucinations which is different than a person having gender dysphoria; so the schizophrenic would need to be on medication (most likely) to not pose a significant risk to others (depending on how bad it is); whereas that’s not the immediate case with gender dysphoria. The biggest risk it to themselves, like a chronically depressed or suicidal person. Because of this, the approach is a bit different: I think we would have no right to force them to take any medication unless it something proven to be analogous to the schizophrenic example of taking meds to not hallucinate; and we would take the approach of having governmental and societal institutions and programs that help consenting transgenders get better (like alcoholics anonymous).
For homosexuality, it is not a mental illness by any stretch of the imagination: it’s a pyscho-sociological (at worst) or pyscho-physiological (at best) phenomenon. The harm they, as consenting adults, are doing to each other I would view analogous, although not quite the same, as heterosexual couples that perform effectively the same sexual acts: physical force or punishment isn’t a proportionate response and it wouldn’t make sense to do so. Instead, there should be programs for helping homosexuals with their sexual orientation issue and for helping all couples with their sexual vices that are voluntary. Socially, we should love those who are sinful—which is all of us—and try to live by example so that people can see that what they are doing is evil and everyone should be readily willing to help them be better (and quick to judge nor to condemn).
I think a lot of liberals think that being against homosexuality and the like has to lead to homophobia; but that’s just not the case.
I assume that all else being equal you would prefer to live in a society in which the sexual activities you think are immoral are at the very least stigmatized, no?
It depends on what you mean by stigmatized. I would say that the family and friends should love them (in the eudaimonic sense) and be kind to them and live by example to try and help them onto a better path. We are all sinners; and we should live by example proportionately to what we know about the good.
Like I said, if the person is posing a significant risk to themselves or others then physical force may be a reasonable response (for their own good and the good of others).
3. It leads to a more humane society: no loving couples are stigmatized (privation of goodness, mental illness, etc) because of their private consensual acts.
But, again, ‘humane’ here is begging the question. Also, ‘loving’ is being used incoherently here: you can’t harm someone with love (which goes back to our differences in our understandings of love and harm).
Ultimately, I think liberalism and conservatism in America boil down to four concepts at play that are really influencing the differences between the two. That is, love, harm, freedom, and goodness. We are not using these concepts the same at all.