Okay, I'm MTF, but the same concept applies. Why don't I just stay a man and be myself? Because "myself" is female and trying to be male has always been an act and performance of hypocrisy for me. People with no understanding of gender dysphoria can't comprehend that our outward anatomy doesn't define who we are, and is in fact at odds with who we are.
Imagine if somebody had some congenital birth defect that caused them be born with three arms. They lived for, let's say 20 years with a third arm, hating it every day. It is cumbersome, feels ugly, and the surgical technology to remove it is readily available. Yet people keep telling this person "Why can't you just accept that you were meant to be a three armed person and embrace your three-armed-ness?".
No reasonable person would expect a person with unwanted appendages to live with them. Yet if a transgender person says that their anatomy as it developed biologically causes them distress, they are somehow crazy.