Well, as you can see from the film, Ben Stiller is obviously taking himself seriously. He's working toward his Oscar nomination with films such as this, obviously. You have to expect everyone involved in the film to take themselves that seriously.
I'm pretty sure they will mention other controversial topics, such as on which side of your head should you part your hair, and how high should pants be worn?
Asking the trans community to not take seriously when a serious actor has some fun in a no-consequence film is clearly out of the question.
People like this rustle my jimmies.