There are words that are, in present society, perjorative and they should be avoided. There is no reason to deliberately denigrate any group UNLESS you are a well-known part of that group and even then it's a risky business.
One of the greatest comics of our time, Red Skelton, never used profanity and if he did take a shot at a group (the folks out here in California...) the dig was very gentle.
I think that anyone who performs has to realize that the most innocent of comments may be offensive to someone. I try never to pick on a group but to go after a specific person. I can usually spot the guy who will go along. I'll introduce a song and then point to someone and say,"Don't worry sir. She'll explain it to you." It never fails to get a good laugh.
But you have to be careful. Sometimes a song that you do regularly will hit someone wrong.
I was singing regularly in a bar called Grogans Saloon in Salt Lake City in 1963 and one of my staples was Away With Rum (The song of the Salvation Army). I was half-way through the second verse one night when this drunk came up out of the audience with a chair shouting that the "Schalvashion Army" had helped him a lot and he wasn't going to let anyone make fun of it.
Big Sandy, the bartender/bouncer got to him before he got to me.
Other than what I've said, I can't think of anything else. I believe it's just a skill you have to develop over time.

troll