Because these messages imply parents want 100% control over their kids, when kids are individuals as much as anyone else, with their own opinions and identities. No one is pressuring these kids to be anything other than themselves, except for these parents who want their kids to be exactly like the vision in their head, which isn't going to happen most of the time (Free will and personality and all that). If the idea of kids being around other cultures and types of people is scary to a parent, they need to think about who's grooming who.