I have a crass sense of humor especially if others are laughing
There are many young people nowadays who have crass senses of humor.
Yes. I don't think it's bad if it makes people laugh.
You definitely should have a sense of humor but that doesn't mean you should laugh at others expense. YOu're being insensitive to find crass jokes funny.
What I find funny is not wrong or insensitive. You need to stop being sensitive to all sorts of things.
While the jokes may work to make other people laugh, try not to do it at the expense of anyone else. Just because a joke is funny to the people laughing, does not mean that the person being made fun of is going to be ok with it as well.