You're basing that on:
1. Some Small Heath knuckledraggers swore at you.
2. Some Brummies annoyed you on holiday.
3. Someone shoulder barged you during a match.
I'm from Birmingham, and I not only do not have a regional accent, I don't have a chip on my shoulder, either.
Your post is a bit like people seeing that photo of the Newcastle fan twatting that horse and saying "Fuck me, Geordies, they're all insane, I saw one twat a horse once. Well, it was in the paper, like. They're all horsetwatters, honestly"
Seriously, what rubbish.
I was coming out of a Newcastle - Villa match at your place in the late 80s, there was a bit of trouble, and one of your fans stuck a house brick in my mate's sister's face from point blank range.
Did I spend years blathering on about how Geordies brick girls? No, I didn't, because I realised it was about one fucking twat, and fucking twats are fucking twats, wherever they're from. And they're everywhere.
Here here