You know you can make a character without it, right?
I don't get why this upsets anyone. Be mad about transgender surgery if you want, makes no difference to me, but do something constructive about it - not playing this is not that. I have no issue if someone who is transgender wants to play this, and uses the option to create a character they feel represents them. Equally I have no issue if someone wants to roleplay as a transgender character for some reason, or if they would never dream of turning this option on. I won't, but what harm does it do to me if someone else does?
I note the options seem to be on or off, so it's not being forced on you.
For the record, I am not pro-trans, or anti-trans or whatever those sides of the argument are these days - I am don't care-trans because it's none of my business.