I think this is a very homophobic comment to make. Why would she tell her friends her ex was gay? To be spiteful? To ruin his life? Is she homophobic? Does she not know how many people KILL themselves every year because of comments like this?
Does she hate the gays and are Taylor Nation trying to cover it up?
It is obviously with the intention that no other girl would date him and he would be forever alone and miserably, because he hurt her. Nothing homophobic about it.
She also wrote that song when she was 15 and changed that line for the album release.