I think for the most part young people are okay at that though. If an old grandparent says something a bit racist that wouldn't be allowed today, I'd imagine for the most part it's "ah it doesn't really matter, they're from a different time", rather than actually attacking 90+ year olds in the streets for it

.
I think there's an element of extremity being publicised because that's what sells. I'd imagine the actual number genuinely offended by the word in the song are incredibly low, and so the more 'extreme' opinions get more spotlight because they are extreme.
That said, coming out is extremely difficult, so if I had a mate who was gay and was offended by it, I'd probably stand by him. I don't think it's as clear cut as some are making out. No one is really offended by the word because they know the context, but is it something we should all be singing every year? I suspect not. I'd argue that if you're acting all angry on
either side of the argument, then you become one of the people you yourself are describing.
You are right though, you definitely do see people being offended on behalf of other people for no real reason. Often when the 'victims' themselves couldn't give a damn about the offending word or whatever it is.