Those establishments have the right to let whoever use their bathrooms. If the business is pro trans, and owns the land like a Target, there is little doubt you can grandfather your own decision to use either bathroom based on what you feel is appropriate. If some other person has a problem with that, target, or whatever business owner will tell them to fuck off terf.

Land ownership is a huge deal in America, like your mom's house, whoever owns the establishment and the land, makes the rules in all private scenarios. No shirt no shoes, is this exact same power. You are trespassing if you don't follow the rules of a transphobic private establishment on the contrary.