I'm confused, I don't really see a whole lot of idiot fans, though I'm a new fan myself I admit. Are we talking about new fans that actually create doujins and remix music and art about Touhou or something? I wouldn't really know anything about that, I'm a fan of the games.
I don't really care for anime, though I admit that there are probably some out there that I would actually enjoy watching, probably more than some people in the world that label themselves anime fans. I simply have just chosen to not spend my free time trying out something new on watching anime rather than trying something new that I KNOW I'll enjoy (such as new games).
I'm a bit of a jaded soul here, but people are saying the internet is full of idiots, but I honestly don't really think it's any worse than humanity as a whole. Arguing on the internet really isn't any more stupid than arguing with someone that isn't directly related to you irl. But generally when I find myself arguing over the internet, my goal isn't meant to try and convince the other party that I'm right and they are wrong, but more so to point out that I'm right and they are wrong to 3rd parties that aren't really decided about the subject.
I suppose I'm rambling on randomly but really the op's post is a bit odd itself. Regardless of if you think someone is stupid or wrong or whatever though, I find alot of people have a very hard time maintaining any level of objectivity however. For example if someone you perceive to be an idiot says something, it's generally automatically assumed to be idiotic and wrong, regardless of what it says...Which in itself is dumb.
In the end however we are talking about fans over fictional entertainment. It's almost a matter of liking one color over another (speaking of which why do more people paint their cars 60s puke green, puke brown, puke orange, than something like purple? whyyy >=P ). Just enjoy the fact that there are more fans about something you appreciate, since it only supports the production levels of future products.