I think a lot of the "hate" or criticism of younger kids like yourself, and even to an extent me as an almost 18-year-old (3 motherfucking days, Thursday baby let's go) is the fact that people remember their times as a younger gamer and just want to fuck around with what they used to be like. I can only imagine what people like @Josh @Tiger or @Dev(sorry just the first people that came to mind who seemed... umm... totally not old) remember from their younger years. Ask them, see what they remember hearing from that "old guy" fuckin around with em. If it gets to the extent that you are truly hurt or even just annoyed tell them what's goin on and that it's annoying and you'd like it to stop. I do think another reason is the higher pitch voice. Look, we were all there at some point in time, that high pitch "squeaker" voice. It was only 6 ish years ago for me. Just try not to mind it, look at their criticism as a point of those people remembering what it was like for them when they were a young aspiring gamer.
P.S. I don't hate ya. I love playin with you even if your voice is a higher pitch than others. Keep on *ehem* NOT RDMING *cough* xD Just have a great ass time!