I think it’s more about how you are treated.
Picture that starting tomorrow, everyone calls you “Frank Duncan”. Your ID says it. Everyone says “Hi, Frank” in the morning. When people go on vacation they bring back little souvenir doodads personalized to say “Frank.”
Frank is a perfectly fine name. And it’s not like there is anything objective in the name you were born with. But it’s not your name. It’s at the very least disorienting to have everyone call your “Frank Duncan” when that just isn’t who you are. And yet every time you explained, they just point at your ID and say of course you are Frank.
That’s annoying enough. But transgender people are also living with something they are often uncomfortable with. They may be scared or ashamed. They may have heard terrible things from their family and friends.
So when you picture yourself being called “Frank Duncan”, imagine you also harbor what you consider to be something deeply uncomfortable about your name. Maybe you were disowned at birth, or named after a Nazi, or something else you may feel shame and fear about having exposed.
And now you are here with people falling you “Frank” all day, each time poking that little wound. Each time reminding you that you are not normal, but rather stuck in this state where you can’t convince people that you are who you are. And furthermore you are uncomfortable and ashamed of even that.