While I too kinda roll my eyes when someone gets upset about how someone is dressed (because I was friends with plenty of people who liked the goth look in high school and college and how they dressed had nothing to do with what kind of person they were),
You know you may have had friends that "liked the goth look" but apparently it didn't make enough an impression on you to think that maybe, like your friends, this person is making blanket statements and accusations about this group of people.
I'm sure my friends and I were all painted with the same brush by neighbors too, but not all of us smoked pot, not all of us dropped cigarette butts, and it was the preppy kids who did the graffiti and vandalized houses (but the police showed up at my door and my friends' door). She has witnessed some kids smoking pot, some kids smoking. She doesn't know who did the graffiti, she doesn't know who urinated in the area, and even if it was "those kids" she doesn't know which ones. Some of my friends did coke and stole cars, but that was a couple out of the group, and they were sort of on the fringe of our group at that. But they were still people I would stand on the street corner bsing with.