2. Bad kids who were always and will always be bad kids.

Further, any interaction between a bad kid and a good kid is strictly making things worse for the good kid.

My experience in K-12 proves that this is in fact largely TRUE.

" Being around "bad" kids is often good for "good" kids. "

This is just a mind-numbingly stupid take. A 10th grader taking advanced calc and programming robots doesn't benefit from being forced to interact with an illiterate 19 year old who has been held back 3 times and steals his lunch money every day. This is in fact almost a human rights violation for the smart kid.