In hindsight you are right, but I'll give you the mentality that 14-year-old-me had:

Basically, the idea of being racist is so absurd, that by being ironically racist I'm poking fun at the racists, not the races.

It's not a completely ridiculous notion (though it's abused heavily); satire is a common tactic for comedy. Clearly people go too far, and I don't think it's a good excuse to say "it's just satire".

The same way you can be ironically anything. It's not immune to modifiers just because it's offensive.

I mean, I do think it's way too easy for someone to say something horrible, and then get off with no consequences because they claim it's just a joke (or locker room talk... cough).

I'm not exactly sure where we draw the line socially. I don't really have a problem with something like The Colbert Report, but I also really hate the "shitlord" movement that seems to be happening.