Mostly agreed about your meta point. I think you're omitting the possibility that someone might be opposed to something that benefits them.

But in the non-meta discussion, all I'm saying is that you don't know which commenters are in which situation, and especially not with 95% certainty, like you claimed. Some of the commenters might oppose rent control, even though they benefit from it. Other commenters might strongly support rent control in San Francisco, even though they live in Wyoming. We just don't know.