Yet, if you ask any man, do you want to be any shorther? They will most likely say no.
Men have animal insticts towards eachother. Who is toughest, who's the best and strongest. Your stepson probably LOVES the power of his height when he is around other men. And not everyone is 226cm, you can be 180cm and be tall and avoid all issues with doors and riding busses. If you're tall you can be both a police and a rugby player, if you're short you have to limit yourself.

As you said, no one likes feeling overpowered, your stepson will never have to feel that. He doesn't have to prove to himself that he is strong and big, that comes automatically with his height because that is how people see and precept him.
When people commplain about being tall, I laugh. When tall people bring up that they can't fit their legs while sitting on the buss, I think to myself, well lucky you that you don't live on the buss then, because when you step of that buss, it's all good again, while when I step of the buss, I'm still short and my height issues still remain, and lucky your stepson that he doesn't live under a door frame.

I can't deal with having to pick a job or a profession depending on my height.

Random Dude: Hey Oliver, why are you a Rugby player?
Me: Because I'm short.
Random Dude: Okay, but you you like being a Rugby player?
Me: Nah, but you know I'm short, soooooo.... *sniff*.

And maybe there is a girl out there who would like me, but then I would never feel like I could protect her against larger males, and I would feel almost ashamed meeting her taller friends who look down on me like my mother did when I was 8 years old.

Lets be real, girls want a nice guy, but they also want someone who can protect them and whom they can feel safe around, I guess they also want someone who can make them look good. I can't offer any of that, exept for the nice guy part.

Search this on youtube, I can't post links: Short Man - Sidewalk Experiment: How short guys get the short stick

That video only showcases one of the short mans problems. I remember in ground school, walking in the corridors. I had to squeeze myself along the wall to get through. Do you have any idea how humiliating and downgrading that is. Not even the girls moved for me.