AITA for telling my girlfriend to take off her "gay rights" t shirt.

My girlfriend was bi, I'm a guy. She had only ever been with girls before me.We've been together 4 years.She grew up in a small town and got a lot of shit for being Bi and even had physical assaults and damage to her property when people found out she's not straight. She always felt unsafe there and then moved to a city where she met girls and lived her best life or whatever.We met and fell in love and all is well.We had to go back to her home town last week and I was meeting her at my work to go. She picked me up and was wearing a jacket and t shirt. She got out of the car to out in petrol and I saw that she was wearing a t shirt saying "homophobia is gay".When she got back in the car I asked wtf that was about and she said it was because she could never be out when she was younger and she wanted to wear it as a fuck you to any of her bullies she bumped into.I told her that's petty and that she's using her sexuality as some emotional blackmail thing. I told her that she can't go to her old town with her BOYFRIEND and rub in everybodies face that she's a gay woman, which she's not.She got upset and said she is a bi woman, and that she identifies as part of the LGBT community despite being with a man. She said she wants to be proud but I said it's more homophobic to wear that shirt because she's acting like she's special for having been with girls.She's in a straight relationship, living a straight lifestyle so she needs to move on and get over what happened. She can't expect special treatment for being "queer" (her words) when she isn't even part of that lifestyle now.Anyway, she's fell out with me and said I'm an asshole and I was just adding to her insecurities by trying to erase her bisexuality because I'm a man, she says that doesn't change her sexuality. Really, AITA?Tl;Dr girlfriend wanted to wear a gay slogan t shirt out but I don't think it's appropriate.Edit - yes, I know what bi is and I know what it means. I'm not dismissing or erasing bisexuality. No, I don't control what she wears. Its like if I went on a date with her wearing a t shirt saying "I like blondes".Edit 2 - I had no idea this would blow up the way it has and it's almost a unanimous YTA in the comments, I get it. However I've received over 300 messages saying I'm NTA and that speaks of a larger issue - people are so quick to defend LGBT community that anyone with an opposing or different view is silenced and won't comment because they'll just get downvoted to fuck. I've read as many comments as I could, all are saying about the same thing. At this point, I've given up reading them cause there's just too much but I guess it's food for thought however I stand by my opinion and I do not believe I'm biphobic. The only good advice I've gotten from here is to break up with her, not because I'm an asshole and homophobic, but because we're fundamentally different people with opposing opinions. via /r/AmItheAsshole https://ift.tt/2CPNBcr