I don't think that it's accurate to call transgenderism a delusion. It's not like transgendered people are unaware of their biological sex, rather, it's not incorporated into the self-concept because it wasn't something that they willed- it was decided by external factors and so it isn't really representative of them as personal agents. It's relegated to a facet of or an imposition of the environment instead. There's an internal dissociation between the authentic self or potential self of the mind and the externalized body, the body that you, as an external observer, instead associate with the mind and see as whole. Modifying the body attempts to rectify this dissociation by making the image of both the body and the mind congruent. A transwoman will be adamant that she is female because she is female "at heart", and it is the psyche that you communicate with when you communicate, so it comes as no surprise that there's a miscommunication when you believe you are communicating with an entity that is not fractured between mind and body (the two are seemingly united, you view them as one entity) but, from their perspective, very much is. The phrase "you are male/female" or referring to them by their biological pronoun is interpreted as an attempt to define the psyche, and is met with resistance. The "you" that you refer to is different from the "you" that they interpret you as referring to.

The question is whether it is more ethical to modify the psychological essence of someone to fit the body, or to modify the body to fit the psychological essence of someone if bringing congruency to the self-image is a goal. Another question is whether a person's ability to modify their circumstances is to be respected, or if their circumstances should instead modify them. If a transman were technologically able to alter his genetic code, would you accept him as male once he did? Knowing that the only thing that bars that transman from altering his genetic code is an inability to do so, is his identity less valid because circumstances do not allow for it to be actualized, despite having the clearest image of what that identity would be if it could be? It's a case of "I have no mouth and I must scream". The mouthless entity screams internally, but nobody believes it because on the outside, there is no indication of it. Graft a mouth on and suddenly it becomes clear that it's not that it was never screaming, only that it couldn't manifest its screams. To the integrated person this doesn't even occur as a possibility because their bodies have been beneficial to them rather than constrictive.

It comes down to how you see people, I think. It can be extremely hard to understand the psychological essence of someone when their external presentation so greatly defies it. All that being said, I don't think that a person has the explicit right to force others to see them the way that they see themselves- transgendered militancy is an unfortunate side effect of miscommunication and a desperate need to self-actualize. But I also don't think that someone has the right to force others to see themselves the way that they are seen by that someone. I see our ability to define ourselves as one of the hallmarks of what separates us from animals, and I think that attempts at actualizing our identities, however imperfect those attempts may be, are progress in respect to normalizing a freer mode of existence. Obviously transitioning is on the whole a work in progress technologically, but the attempt is to be respected, rather than giving into the will-less existence that is choosing not to define oneself.