Taylor examples:
Welcome to New York
When we first dropped our bags on apartment floors
Took our broken hearts, put them in a drawer
Everybody here was someone else before
And you can want who you want
Boys and boys and girls and girls
And
Seven
And I think you should come live with
Me and we can be pirates
Then you won’t have to cry
Or hide in the closet
And just like a folk song
Our love will be passed on
just two examples. There are more. Music is funny though and can be interpreted so many ways. She has done lots of other things to indicate she may be more than straight. The days she releases music, the donations she makes to LGTBQ charities, the videos with lots of gay people in, circulating a petition to pass the Equality Act, which would prohibit discrimination based on gender and sexual orientation.
All these things can be tied to being an ally. But you know rumours.