Are you saying that people who's children do not go to the school complain about your child's school?
Personal attacks and spreading false rumors are obnoxious tactics. Informed discussion and debate regarding public school budgets, policies, contracts, programs and results are fair game though (although not in a way that corners unwilling parent participants). In our area, every homeowner pays dearly for the public schools (10% property tax increase each year for at least last 6 years). Most residents whether they have students enrolled or not, are interested in the quality of various school programs, assessment results and how their money is spent (which isn�t necessarily in a way that benefits the students).