Earlier quoted context omitted.
At the end of the day it’s your users’ problem. Ideally their assistive tech would work, but if it doesn’t and you’ve got an easy fix then you should implement that fix.
I disagree. Of course you could fix that. But that would mean that you can fix a thousand and one issues that's caused by other softwares erroneous content handling. Which leads to nothing but bloat and introduces just more code that could come with more bugs. If your software works and is designed as intended, then sometimes it stays the users problem. Unfortunate, but otherwise problems will stay forever.
(If you need a personal story to bring it home, the only way my dad, a programmer in the 70s-90s, could continue to use computers when he suffered from MND / ALS, was to use voice control software.)