I suspect that if you went to a political site that was strongly catered towards the "stay" camp and took a "leave" position, the results would be about the same. The problem is that both sides exist in a self-reinforcing echo-chamber, but they both think that it's only the other side that's ignorant, conformist, and unreasonable. Arguing that the other side is wrong because there are stupid people who support that position for stupid reasons is implicitly arguing that there aren't any stupid people on your side.

If you point to instances of people with idiotic opinions disagreeing with you but you ignore all the idiots who are on your side, you have a huge cognitive blindspot and cease to be credible except to other people with the same blindspot. For instance, your last sentence clearly shows your biases: you skipped over all the comments on this thread that are in the exact same tone, but share your opinion.

In general, there is no point in discussing things with someone who is unable to summarize their opponent's position in terms that the opponent would agree are approximately correct. If you can't get to that point, that demonstrates there's not even enough common understanding to have an argument, since you don't even know what the other side is, or if the person you're talking to is a fair representative of it.