People can do what they want. Your body, your choice and all that.
Basically, im not a fan of gender as a concept. Im not sure exactly when it was made a distinct thing from sex, but I dont really see the point. Every case is different of course, but if someone born as a female identifies as a male, I would like to better understand what that actually means. My proposition is that there are a set of societal expectations, stereotypes and behaviors associated with being male, and those are what the person identifies with. In my mind, in this case the real issue is the existence of those stereotypes etc - I am a believe that anyone should be able to do anything. I like bubble baths, and drink fruity cocktails instead of beer, it doesnt make me any less of a man and I am entirely comfortable with my sexuality.
There is of course a lot more to it than that, but as I said - what does it mean to identify with a specific gender? If not behaviours/stereotypes/societal expectations then what?
To reiterate, I have no issue with trans people or anyone else. People can broadly do as they wish as long as it doesnt impact others. I just feel like the topic deserves a little bit of deeper diving to try to understand the root cause of what makes someone want to change their gender/sex (which I am aware are different things).