So why not say the universe is the cause of the dynamite stick explosion, indeed?

Assume we have the following causal chain:

1. big bang occurred->
2. earth formed ->
3. evolution of multi-cellular organisms ->
4. evolution of trees ->
5. invention of matches ->
6. applying this particular lighted match to this particular dynamite stick
==> "boom!"

Given this chain, we can say that the explosion was brought about by any one of these six cause. But only #6, the lighted match, was the explosion's immediate cause.

Combining this chain with your statement that cause and effect are proportional in magnitude, we now have the following entailments:

The magnitude of the dynamite explosion was proportional to the magnitude of ...
the big bang,
the earth being formed,
the evolution of multi-cellular organisms,
the evolution of trees,
the invention of matches,
the lighted match.

By this logic, the assertion that "the magnitude of an effect is proportional to the magnitude of one of it's causes" has now gone from incorrect to incoherent.

Furthermore, this line of reasoning is just a distraction from the real issue at hand, which is:
what is the analogy between karma and human cause and effect?

From the point of view of natural selection, it matters not whether an organism lives a hundred years or two minutes, or if its life is filled with joy or agony, so long as the organism successfully reproduces

This is not the whole story. Natural selection is properly understood as acting on populations. All other things being equal, the portion of a population undergoing some agonizing stress will reproduce less successfully than that portion of the population not experiencing this stress. This is assuming that the stress manifest itself in such a way as to negatively impact pre-breeding survival rates.

Some people call psychedelic experiences more real than reality.

Here's an example of the difference between reality and psychedelic experiences.

As a geologist, I mapped some of the rock units in a particular quadrangle in the Wasatch mountains of Utah. Another geologist could go out and map the rocks in the same quadrangle and our maps would be more or less identical. Why? Because these rock units are objectively real features of this particular quadrangle in Utah.

Now take my geologist friend and I and put us in the same room and ask us to describe the color of the room. We both answer "blue." Now give us a hallucinogenic that is know to effect our visual cortex and then asks us what the color of the room is. I say "orange" and my friend says "green". As the experience continues, I later see it as "yellow" and my friend sees it as "red."

So which color is it - blue, orange, green, yellow or red? The room cannot logically be all these colors at once. It's a fundamental axiom of rationality that something cannot be both itself and not itself in the same way at the same time. The room cannot be simultaneously both blue and not blue (ie. orange/green/yellow/red).

So what's an alternative explanation? Could we say there is no objective fact about the color of the room? Should we say that our perception of color does not map itself in any consistent way to the world around us? Is our color perception purely subjective?

Okay, let's imagine the following experiment. There is a tribe of ancient hunter-gatherers, half of whom see tigers as orange things and half of whom see tigers as sometimes orange or green or yellow or red. What will happen over the long term. I submit that those who cannot consistently distinguish between colors will be at a selective disadvantage. Over time, natural selection will weed out the color compromised group.

The moral is this: if our senses are not reliable enough to reasonably detect threats in our environment, then humanity's survival is either a very happy accident or a miracle. So, yes, there seems to an objective reality around us.

As far as I know, all animals have an instinct for self-preservation. This instinct has been safely lodged in our genetics since time immemorial. It is not going to be selected against anytime soon, IMHO.

Sometimes this instinct is overridden by other instincts. For example, the male black widow spider who mates with the female even though he will most likely end up being eaten by her. Or the female salmon who hurries to her spawning ground even though she will die soon after getting there.

As human beings, we are not fully controlled by our instincts. We are capable of acting against them. That's why a fire fighter, for example, will go into a burning building even though his instincts tell him not to. Or a mother risk her life to save her child.

We have the capacity to act against our instinct for self-preservation. We seem to do so when we have a more compelling personal reason overriding our self-preservation. We label such actions as self-harm when the reasons seem to motivated by mental illness.

Monism, the belief that there is only one metaphysical reality, is widely held by contemporary philosophers. This was not always the case. Up until the enlightenment, dualism, the idea that there are two metaphysical domains, the natural and the supernatural, held sway. Science (aka methodological naturalism) as a form of monism, has been instrumental in debunking the supernatural. Philosophical naturalism, another form of monism, has also provided powerful arguments against dualism.

I'm not sure if a strict philosophical naturalism is popular with the American public. Most American are religious to the extent that they believe in a supernatural "higher power." This would seem to put them in the dualist camp although their dualism seems very restricted -- ie. yes to god and angels but no to fairies, pixes, unicorns or magic.

@LidaRose states:
If absolutely nothing ... occurs then time ... does flow (exist).

I would think that absolute nothingness would lack everything, including time. I'm guessing this is a typo.

In fairness, the American education system has some advantages compared to other countries. In the English speaking West Indies, the primary schools are modeled on the British school system. Where we lived, children had to pass the Common Entrance Exam to be able to go on to secondary school. At the time, the number of students who passed the exam was low. There would be villages where only a handful of students would continue their education past the age of 12 or 13.

@KenoshaKid states:

What's been drawn is an analogy. In defining their religion, the Buddhists have incorporated a kind of causality, specific in its relation of human causes to effects, but vague in the mechanics.

What then is the analogy? Perhaps you could spell it out because I'm not seeing it.

Are you saying that karma is analogous to human cause and effect? But human cause and effect is often morally ambiguous. In this world, sometimes the morally evil prosper while the righteous suffer.

Or are you saying that karma is analogous with some notion we have of poetic justice. But poetic justice is not an objective state of affairs but a desire. Poetic judgement is rendered when we see someone get what we but believe they deserve.

It seems to me that karma is like hell -- it's a kind of delayed but infallible punishment invented to satisfy our need for moral order.