I agree, in general. However, my son was graduated from Masterman (school for gifted and talented) and most of the kids he knew went to Masterman or other magnet schools, either for the arts or science. None of them had the criminal element you speak of. This was in the early 90s. Even years later, I doubt Masterman has a criminal element.
Masterman was a safe, welcoming environment. When my husband died when my son was in 9th grade, I couldn't have hoped for a more warm and understanding school for him.
The difference in private/charter/parochial schools and public schools in Philly is astronomical. The regular, public schools are absolute Hellholes. Even Central High — which is supposed to be one of the “exclusive” public schools — is pretty frightening.