Pay no mind to them, there are way more nice people than mean people. Young adolescents are notoriously mean but they're just projecting insecurities they may have, or they may be trying to show off/impress their friends by being dumb. Unfortunately some people will behave this way, its best to try to stay away from them if thats how theyre going to act. Telling them to go fuck themselves will only make them act even foolish. This kind of behavior usually stops after a certain age, you've got to be able to manage it, get some good friends who value you. Dont let anybody treat you like a clown and dont let your stuttering make you feel like a clown. You are nobodies entertainment. Your stuttering doesnt define you or your capabilities and it could always be way worse (i know, i shouldnt say this) but i'd rather stutter than not have an arm, catch my drift? adapt and overcome, specially stupidity.