What you are trying to write about public school is derogatory, these are public institutions that are well funded by government, for the fact that there are some students that involve in some of these illicits behaviors you did mentioned doesn't mean that it was the fault of the school management, it can be as a result of peer group influence either from their homes, because the school does not teach those kind of morals. Most of these pupils have gadgets that are internet connected in their houses and most times they browse to see some of these things from their home, the school has limited access to what they can do, some times the parents needs to step in to make this correction.