Given that school district policy is to allow students to wear clothes expressing political or religious opinions, the school doesn’t have a leg to stand on. No way in this day and age is there any kid old enough to read who isn’t already at least somewhat familiar with the abortion issue, so I don’t by the “disruptive” claim. Personally, though, I don’t think schools should allow clothing carrying any kind of “message”.
Er, yes, I DO know the difference between “by” and “buy” . . .