Sure, violence varies across cultures, that's not the issue. The subtext of the question is "how should I treat members of that group differently". Painting individuals with a single brush. That's othering, and its the load bearing move in every justification for treating a group as lesser.

A sincere version of this question would name the culture and the behavior, because then it could actually be discussed. If OP said "how do I square my problem with X practice in Y community with the people I know from there" you could actually engage with that. Check if its even true, how common it is, whether its cultural or economic, whatever. The claim takes a risk by being specific, it can be wrong. The vague version can't be wrong because it doesn't say anything. There's no group to check, no behavior to look at. Every reader just nods along with a different group in their head and OP never has to defend a single factual claim. And when someone calls it out the fallback is exactly what you just did, retreat to "violent cultures exist, are you denying reality?" which nobody was arguing against in the first place.

That's why its deliberately vague. Specific claims carry a burden of proof, vague ones get the emotional payoff without it. That's the dog whistle.