Again, this is a difference in site culture you'd pick up on if you lurked more. Nigger is just a meaningless insult like calling you a faggot. No one knows or cares if you're a homo, it's just shitposting. Same with nigger, retard, autistic, kike, etc.
Some people here are racists. That's because we accept and appreciate people from all walks of life, even if we think they are assholes or don't agree with half of the things they say. Being one of the last places online that's all about (mostly) free speech attracts all kinds of people.
Most of us just like being able to say the so-called forbidden words because we cannot say them literally anywhere else. It really isn't that deep. We're just edgy autistic shitposters.