Perhaps it's more nuanced than peers v. parents. For example, it can be:

Bad kids -> your good kid

but also

Bad parents/trauma -> one child with a dominant personality -> outsized influence on peer group -> your kid.

All that said, if I had a kid I'd spend every penny to segregate him/her with other kids away from average dodos. I had a terrible experience as a kid surrounded by imbeciles and bullies, which changed after I went to a better school.