It's a classic case of correlation is not causation. Yes, there have been societies where men couldn't form families that were violent (like the Wild west in the US) but that doesn't mean that that was the cause of it.

Similarly, many on the left have long thought that porn viewing causes sexual violent crime against women. And there is ample evidence showing that men who view porn are more likely to be sexual offenders than non-viewers. But then came the internet and the amount of porn and porn viewers skyrocketed - but the amount of sexual violence against women didn't - therefore busting the theory.

In the same way, evidence from Japan, China, South Korea and even India means that there can't be a causative link between family formation being unavailable for young men and civil unrest.

Perhaps these counterexamples are evidence of additional factors, in cancer or in unrest, but they do not prove that a causal relationship doesn't exist.

Do you conclude that the overwhelming abundance of data that shows that smoking causes lung cancer is wrong? That there cannot be a causative link between smoking and cancer because there is a counterexample where it didn't appear? I would say that these other factors are also having an effect of comparable scale.

Data suggests that social unrest in China has increased in correlation with incel count. I would count that as supporting evidence for the theory above. But you're saying, correct me if I'm wrong, that, because the initial rate of unrest was so low, and the increase didn't push that rate above that of other countries, incels cannot be a causal factor in unrest?

Help me understand where we disagree here. What part of ´inability to start a family->unhappiness->social unrest' do you think is questionable?

Regardless of the theory.

I have found such X. In principle you agree, but you want to save your theory so you say "Well, if X and not Z then Y!" and that explains my counter example because my group probably had Z.

Here Z being the racist idea that Asian people are less violent than others and that that's why social unrest hasn't erupted in their countries.

You might be right. But then your theory is "inability to start a family and non-asian -> social unrest." Clearly, not the same as "inability to start a family -> social unrest."

Back to cancer, heavy smokers who did not develop cancer are an example of some X for which X->Y is false. Like you said, you would need to take a random sample of cases and see whether Y correlates with X against a control group.

You introduced the concept of Asian countries having lower rates of social unrest, and I have never said this is related to race at all. Perhaps you are reading into the genetic confound in the cancer example, but it was just intended as an example of a confound within the analogy. There are plenty of differences between life in these countries and elsewhere that can act as confounds.