No it's not. It makes no sense to say "oh, you can't commute to work and then home again five times a week? so how do you get groceries?" because those are two completely separate things in completely separate environments.
It's none of Amazon's business how people manage their disabilities outside of work. The only thing that matters is what the most effective way of managing their disabilities is inside of work. Amazon is not your doctor, and if your doctor says that this is the most effective way for you to manage things while being productive then they need to accept that the doctor knows what they're doing.
If a guy asks for a special chair because they've got an injury? I probably ought to check whether they're OK standing for long periods, whether they're OK with carrying heavy things, whether they're able to self-evacuate in a fire, etc.
There is a limit and a line though. What Amazon is doing here is actually pushing the line much further than most employers do in my experience, especially big corporations. usually, they'll simply take the recommendation the medical professional gives at face value. Amazon is purportedly not doing that.
In fact, the way they worded it, I can't help be feel at least a slight annoyance they even have to accomidate disabilities to begin with.
They are allowed to ask for medical documentation on what your limitations are.