I can hear a parent saying, “I don’t want my kid’s friends to do things that will negatively affect them, in turn affecting my kids.”
If so, ain l’davar sof.
Should I campaign to have a kid kicked out of school because they have a non-frum cousin whom they see at family gatherings because “they might influence my kid’s classmates…*” Or their next-door neighbors? Or their summer camp bunkmates?
The point is that you can’t control everything that influences your kids (much less things that influence other people’s kids). Saying “other people’s kids shouldn’t do X because it might influence my kids” is a fool’s errand.
The Wolf
* True story from personal experience: I grew up not frum (I know… big shocker there!). As a part of her process of divorcing from my father, my mother became frum when I was about 9 years old. I became frum with her.
When looking for a yeshiva for me to enroll me in, one school said that they’d be willing to accept me if she completely cut me off from my father (who remained not frum). She turned them down flat.