If you feel offended by their words, don't laugh with them. Make them feel that you're not ok with it. Let them feel embarrassed and ashamed of themselves.
Being rude to people is not a “culture” but a choice and it’s not something you should tolerate. Some are just being unnecessarily mean for no reason and that shit’s tiring. You’re not gonna earn anything from that. You can live your life without disrespecting others.