Parents are a pain in the backside(to put it very mildly by my standards). Alot of parents are quite willing to sit on their lazy bums and tell a ref how to do their job. Don't you think that after reffing for 10 years they would know what to do? and the parents that cry, threaten and attack refs... how long have they personally (not as a parent) been associated with basketball. probably never.
Do we tell you how to do your jobs? NO! Is it your job to teach us how to referee basketball? NO! So unless you have the balls to get a whistle in your mouth and ref a game, shut up and let us do our job.