Are you complaining about the “yo mama” joke?
From the uploaded picture titled “wymiana handlowa” I am guessing you are Polish. I totally understand how a “your mother ____” joke is highly offensive. You really have to understand, in certain contemporary parts of American culture, the “mother” in a typical “yo mama joke” is a generic joke setup and not literally about your mother – unless they really went to extreme lengths to make sure you knew they were actually insulting your mother. It is just a joke setup, popularized in the 1960’s.
This is like a “knock knock” joke, where in the joke setup someone is not literally saying “I am knocking on your door”. Or “X walks in to a bar” is not literally about a specific thing actually walking into a bar. Or “Why did the chicken cross the road” is not literally about a specific chicken physically crossing a street.
This joke does not mean the police are outside your door:
Knock, knock!
Who’s there?
Police.
Police who?
Police hurry up, it’s chilly outside!
Anyway, the proper thing to do is report it in-game, not hash it out in the forums.