monstro, I don’t recall ANYONE saying that ONLY black teenagers can be noisy. If someone had, then I think that your story would have some relevance. I’m quite certain that nobody made such a claim, though.
Similarly, I don’t recall ANYONE saying that ALL black teenagers are noisy. Again, if somebody had made that claim, then your objection would be relevant indeed. They didn’t though, so I don’t think that your little anecdoate matters in this case.
Unfortunately, that’s how these discussions often go. If you ask why blacks tend to be noisier than most, you can count on a whole bunch of people to say “What are you talking about? Not all blacks are noisy!” or “Blacks aren’t the only noisy people out there! You can have noisy people of all races!” People should know better than that.
Now, I’ll admit that the OP didn’t specifically affirm that he wasn’t referring to every single black teenager out there… but he shouldn’t have to. He was obviously making a generalization. If somebody says that dogs have four legs, he shouldn’t have to clarify that some dogs have amputated limbs. By the same token, one should have to expect the OP to explicitly state that he wasn’t referring to every single black teen in existence.