But what people have "kindly" explained have merely been justifications for racism and other hate speech that all seem to ultimately boil down to it being normal for 4chan. That, and the excuse of "oh but they don't really mean it" is pretty thin justification.
A very simple pattern of 4chan posting culture is to offend others in order to provoke a debate about what you actually want to discuss. It's the 4chan version of clickbait. The /g/ catalog is absolutely filled with people doing this. Want to talk about Linux? Pretend you're a superior Windows user and mock Linux for not having some feature. File picker thumbnails are a common example. This happens all the time and can generate some rather unique discussions.
Because it's anonymous, you'll see a lot of frowned-upon behavior which can nevertheless be interesting. Everytime some drama happens on GitHub or LKML there might be a random 4chan thread discussing it in the usual offensive tone. It's interesting to read about what people think, especially opinions they wouldn't express if they had to sign the post with their real names.
I do this with investment ideas on /biz/ regularly, particularly in the stock market general thread and have had some very enlightening debates as a result.
If you can't, or rather won't, see beyond that. Then it's just not for you. And that's fine.