Take any niche forum... or any online forum for that matter... and you'll run into 'the angry crowd'. They get mad at life. They get mad at other people, they nitpick, and they initiate arguments that never need to be started in the first place. Earlier today, someone asked about which lens he should get to progress from his 18-55mm lens. He stated clearly what he wanted, what he does with his camera, etc (the answer was that he wanted more reach). The first reply wasn't "here's lens choices X, Y, and Z". He was met with a response that read: "Frankly, do you even know, understand and can use ALL of the functionality that [your camera] has?" The name of the forum-goer who gave the response is irrelevant. I'm not saying he's a bad guy, or that he doesn't have advice to give. What I'm pointing out is the insipid, bashful attitudes that so many forum-goers choose to default to.
Remember that this is a relatively major photography forum. If someone is interested in going pro, and they decide the discussion medium to lay their thoughts out will be a forum, then this forum is a very likely one for them to come to. So, if you're frequently refreshing the "Aspiring Professionals" subsection of thephotoforum, you're obviously going to run into this a lot more. What I'm saying is that the numbers might not be that great, but you're putting yourself at the hub where many of these kinds of people will come to.
Moreover, photography isn't the only trade that people choose to pursue on a whim. Plumbing, carpentry, interior design, fashion design, make-up artists, professional writer, YouTube personalities, artists of all types, professional trades workers of all types, etc... it's not uncommon for people to wake up and say "Hey! I want to be *that*." Most don't make it past the internal thought process. When someone takes it to a forum, that's not worth a lot more than the first stage of thinking it out in your head. I wouldn't be offended by someone saying they want to go pro, they have a prosumer camera and a lens or two, and they've shot a couple vacations. They could be misinformed, ignorant, and overly hopeful. However, few will take it to the next stage.
Remember that photography is one of those things that everyone gets to do. Many people try to be their own lawyer or doctor when they shouldn't be. Many home-school their children when they don't know the first thing about properly laying out a learning plan for a child. The examples are endless. Botched home improvement jobs? Yep, that happens every day. The enjoyable do-it-yourself stuff is what is attractive to many (especially those who are unhappy with their profession, or don't have a professional field they're currently in). And yes, the lazy people do exist who should have gotten a proper education, or stuck with a company or trade, and they didn't... and they just want it all handed to them (but it's not worth getting angry over the most painfully annoying examples). I think we could narrow the go-to easy-to-think-it's-easy-but-it's-not-that-easy list of professions down to maybe a list of 20. Photography is up there. I've run into many (very young, very old, and inbetween) who are terrible with writing, and they are continually trying to be published, or just have others look at their writing. I think what you're mad at is the image of a person who thinks like this: "If I just try hard enough I can do it... I don't actually need to treat this like a path which requires self-education, constant adaption, intense dedication, and substantial amounts of discipline...".