Because it isn't a delusion? Delusions are very specific things in mental health and having a different view of your gender than what society assigns to you isn't a delusion like say thinking my wife is out to kill me which would be a delusion since I don't have a wife.

Gender dysmorphia does exist but it isn't something every transperson experiences. The medical solution to gender dysmorphia is transitioning to your perceived gender.

Basically you are fundamentally mistaken in everything you seem to be convinced of. I think this is a moment for you to ask yourself to what extent are you actually educated in mental health as that seems to be the root of your confusion.