There was a court case in recent memory mandating that universities caption any video they publish. It was specifically relying on the ADA.
https://www.forbes.com/sites/sarahkim/2019/11/29/harvard-uni...
"In the United States alone, approximately 50 million people are considered deaf or hard of hearing. The failure to provide appropriate accommodations to this community is a violation of the Americans with Disabilities Act and the Rehabilitation Act of 1973."