I believe it should be age rated and clearly labeled. But not censured entirely.

I definitely do not want my kids to listen and sing anything like it till they are 90.. er... make that 16 (overprotective mom ) as younger kids will not know the difference between what's acceptable in art and in real life.

But for adults ? No it should not be censored. Your friend should be able to listen to it if he likes it. Doesn't mean you have to listen to it if you don't like it. He was galling you and using peer pressure to get you to listen to it, that is definitely not "friendly".

I've seen censorship close enough, long enough to arrive to the conclusion that the "medicine" is way worse than the cure.