There's been a general replacement of a lot of aspects of club culture with the internet. This has made cycling more accessible and understandable, but also means there are a lot of people out there who've been riding for two years and learned everything on the internet sharing their "expertise." And it's hard to sort the good from the bad. I'm super-guilty of being one of those guys (though I was lucky enough to get some mentoring when I started), but now that I've been road riding for a decade I finally have some glimmers of real experience. I think it gets better if people stick with it, eventually they develop wisdom.
But yeah, the ultimate issue is the club system has become a lot weaker. Partly because it's possible to get info elsewhere, but there are probably lots of other causes, too.