There is no “they”.
Like many others coming from social web, you expect to find some kind of community which fashions everyone shares, an apparel you can put on. The idea is complete opposite: you don't need to follow any fashion, or imagine yourself “part of the team” any more than you want to. Even though it's not written in any rules, you don't have to use slang or tone if you find them dumb, overused (globally or locally), or forced. Neither do you have to treat stupid posts with respect.
I assume that after 15-20 years of being part of collective consciousness, anonymous image boards have mostly the same public as any average site. Amount of crap that you can read there is just the same as everywhere (though in some cases this or that Big Brother hides it from your view — obviously, to make you more comfortable, and spend more time in his warm embrace). The difference is that regular social fashions mandate the use of suitable set of candy wrappers for the crap, then there are customary ways of dealing with them, so in the end people just spend their time wrapping and unwrapping crap, but are proud of themselves, and call it “civilised discourse”.
You're saying that the demographics of 4chan is roughly similar to most any site on the internet?
Well, everyone who wanted to join was able to do it. Constant media attention informed everyone and the dog about it.
Sure, everyone who wanted to join, could. That doesn't mean that the same kind of people want to join orstick around. Even sites like Twitter and Facebook have pretty different userbases, despite being pretty similar.
I guess I should set the reference point.
I remember the time when normal internet users who visited imageboards simply couldn't figure out what was happening, and went back to normal sites (sometimes in disgust). There were no tourist guides written by journalists for the general public. Big forums had informational topics teaching users who “internet trolls” are (starting a short period when any argument which someone didn't understand, or pretended to, was automatically called “trolling”). Someone who used imageboard slang on a regular site was seen as an underage idiot (and certainly looked like one to outsiders), and could find that his accounts with “original” passwords no longer belonged to him (because internet was serious business). Oh, and if someone wrote a post praising some politician, no one needed an explanation that it was a satire that made fun of people believing in “supporting our candidate”.
Compared to that, and after 15+ years, 4chan public is pretty normal, even if it is not exactly the same as on some other site.
I understand now, thank you for the explanation. :)