Cause no one wants to look like the idiot. And when no one has read the article, it's a lot harder to dispute the claims of what the article is about. It's a vicious cycle - someone who hasn't read the actual article makes claims about it, others who also haven't read it react and before you know it, you're ten posts deep, arguing about something that may or may not have happened. All it takes is one person to make an under-informed post and another to pick up on it. The difference between thousands and millions of users affects only the probability of it happening.