Why not, what's wrong with it? What could you do better at home, or what could private schools do better?
There are many kids from low income, broken families who are just really bad students. Bullies. Disruptive. Disrespectful to teachers. It was hell going through public schools in SF.
Basically it's opting out of being around the dregs
I have no other knowledge to vouch for SFUSD either way though.
You could look at college acceptances or similar, but those aren't unbiased either, as colleges look at estimates of class rank, not just absolute performance.