Interesting perspective. What about women in sexist societies who go "I wish I was a man because then I wouldn't have to deal with sexism"? Is that a sign they're "actually men on the inside" or is it a sign that if society treated women better, they would be happy identifying as such?

Simply "wishing to be another gender" can have many different causes, some of which are gender dysphoria, some of which are reactions to a sexist/homophobic society. I would say it's a bit simplistic to say that everyone who has ever wished to be another gender is inherently trans. Some are, no doubt, but others might have other reasons for feeling the way they do.