I'll bite the bullet and say it: If the ADA requires UC Berkeley to take down 20,000 hours of lecture videos[1] because some of them lacked subtitles and some lacked audio descriptions of slides, then the ADA needs to be changed. And any university that commits civil disobedience by not removing such content is making the world a better place.
Arguably they can afford the 3.5 - 7 million dollars but if they aren't reusing the material for current students they may reasonably desire to spend the money elsewhere.
I would argue that you shouldn't acquire an obligation by providing something for free without benefit to themselves.
The ADA may not require it, but the compliance costs it imposes are a strong disincentive for publishing.
The ADA in that case turned an unmitigated public good from "Sure, why not publish them online?" into "We can't publish this content without paying a lot of money we don't have, so we just won't publish it.".
1. https://news.berkeley.edu/wp-content/uploads/2016/09/2016-08...