I don't know the context within in which it will be taught, but in and of itself, I don't see the issue with analyzing gender dysphoria in an advanced high school Psychology class. It's age appropriate and not an uncommon mental issue. Discussing it isn't endorsing it. Nor is avoiding it going to make it go away. Psychopathy is a psychological issue, but no one thinks discussing is going to normalize it or encourage people to become a psychopath.
Of course, it will be depend how its being taught, and I can fully understand that you don't want to give educators the benefit of the doubt, but I don't think dismissing it out of hand is the right approach. Nor do I think making a centerpiece of someone's political campaign is a wise strategy. To me it comes off as phobic and we have much more pressing issues.
I'll meet you halfway on it. First, we're talking about something fairly new. It's only been in the last couple of years that people started saying it's "offensive" to question whether men can get pregnant, puberty blockers are 'life saving' and males should be allowed to compete in female sports. Prior to that, Wat, we had actual sanity. Not perfection, but sanity. With the advent of social media and the Woke Army, sensibility and the real world have taken a back seat to "what can it harm if John wants to be Joan and shower with the ladies?"
Second, in the hostile political climate we're in right now, there needs to be some kind of Mendoza Line. Frankly, I don't agree with you in it being age appropriate... but primarily because I don't think high schoolers should be spending time on this subject matter. I think it's perfectly appropriate to make it available as an elective in college. I'd love to give high school educators the benefit of the doubt but we can't. It's been proven, time and time again the last few years, that personal and political agendas are becoming more prevalent. That's the charged world we live in. Half of my college professors were mentally or emotionally unstable. I knew it then, but that's what electives are for. In part, you choose what you're exposed to.
Personally, I'm neither homo nor trans phobic. I sound like I am, but it's only because I'm sick of having it shoved down my throat. I don't need to see your rainbow flag at every Portland Timbers game because I don't give a rat's ass that you're gay. Neither does anyone else, but you're an attention whore and have to throw your flag in the trunk. Just like nobody cares I'm straight. Right? And this whole 'transphobia' thing is the go to, $ .50 reply to everyone that refuses to call Jack Black in a dress, "ma'am." It's ridiculous. Live in whatever fantasy world you want, but when I see people putting their preferred pronouns on their emails, I can't help but roll my eyes.
We do have more pressing issues.