I just don't know! It's a fallen world out there and people are additionally influenced by pop media, where disrespect, stupidity, and being vulgar is touted not just as the norm, but desired and cool. Stay strong, they are to be pitied, because they are brainwashed and not in touch with themselves or our higher power. This probably doesn't give practical solution you might be looking for, but idk how to deal w these people except to behave add they don't exist at all times. Eventually they likely seek you out in a good way cuz they realize you know what they know about themselves, and that is that they don't matter to you. That being said, don't lose your own values and humanity. Just don't lay your pearls before swine. ;)

I dealt with that issue in my younger years and I wish I knew then what I know now and that's that what others says is a reflection of themselves, it's never about you

Mean people are everywhere. YOu can try to said something back, but it will still affect you. There are a lot books about verbal self defense. On the internet too.