Disabled dude speaking from personal experience.
The main thing is that when you grow up with a disability, your disability becomes intrinsically linked to your identity. You grow up very clearly different from your peers, and have to come to terms with it. Other people identify you as "the guy in the wheelchair" and "my disabled friend". You have trouble dealing with things other people don't, and the fact that you figure out how to deal with it anyway becomes a source of "inspiration" to others. Children point to you on the bus. Strangers walk up to you and call you cripple or midget to your face.
These things all hammer home that you're different. Every single day. So it becomes a part of you. It's a huge part of your identity. You are disabled. You are different. You form communities around it where you know you don't have to deal with the dumb bullshit of able-bodied folks.
You eventually stop being bitter and angry. You embrace it. After all, its a daily part of your life, it'd be stupid to reject it. You finally learn to love yourself. You are disabled. You are okay. There's nothing wrong with you.
You spend most of your early life trying to figure out how the fuck to deal with it and navigate life and be ok with yourself. So when someone gets their legs lengthened or whatever other procedure, it can feel like cheating. Like they cheated. Like... You had to go through all this fucking dog shit just to be ok, and they skipped it. They skipped all the hard parts.
And then you add to that the fact that socio-economic status and economic mobility for disabled people is absolutely fucking awful and that these life changing procedures, pretty much no matter the disability, are all hundreds of thousands of dollars and you have a recipe for bitterness and resentment.
It feels like...erasure. And some sort of weird eugenics adjacent...thing.
I personally have no issue with these types of procedures, but they should be free along with all other medical procedures and shit.