I too have taken a couple of college statistics classes. I think you're misunderstanding/misrepresenting things a bit here. Yes, the internet at large loves to

I too have taken a couple of college statistics classes. I think you're misunderstanding/misrepresenting things a bit here. Yes, the internet at large loves to dismiss survey results for any and all perceived flaw, no matter how minute. That said, they aren't always wrong. In this particular case, everything you've said is true only if you assume a reasonably random sample. If your sampling method itself introduces biases, no increase in sample size is going to eliminate those biases. I'm not enough of a statistician to feel particularly confident in passing judgment over the sampling method here, but I think it's fair to question it, despite the fact that I'm ordinarily far more likely to take the statistics at face value than the average internet commenter.