But a problem with "live as they please" is that they don't live in isolation, so their lifestyle choices can impact others. And trans activism makes impacting other people's lives central.
So, sure they can change their names, anyone can change their name and I'm all for people inventing names and making gendered names gender neutral for babies etc. Anna Lee wants to call themselves Anna Lee, doesn't bother me none. But when they want to force me to say they are a woman, that conflicts with my right to a) not tell lies if I don't want to and b) to be allowed to have a say, as a woman, in what the boundaries of 'woman' are. Denying me the right as a woman to be clear about what woman means - that has a huge impact on me and it will have an impact on all the other female people who come after me.
I don't care if a dude wants to wear a dress, go him! Really don't care. But if he is combining it with an itinerary of gestures and weird lady voice then it is offensive to me, ladyface is at best a mimicking mockery of women and at worst is the public demonstration of a fetish. Both come into conflict with my own personal and political struggles for women to be (culturally speaking) fully human, not fetish objects, not inferior due to not being male.
I am an atheist. I don't go round berating religious people. I believe that they have a right to follow their own beliefs, and I have a right not to follow them. I also have the right, if they are discussing their views, to be clear (in a civil way!) that I don't share them and why. 'Transgender' is a belief and a lifestyle, but it is being treated by the NUS, the media, and other orgs and groups including some within our government, like The One True Religion, like it should be illegal to express any disbelief. Why?