The goal of the ADA is to stop the neverending "well this just affects a few people" and "it's too expensive" arguments against providing equal access. If there

The goal of the ADA is to stop the neverending "well this just affects a few people" and "it's too expensive" arguments against providing equal access. If there's no enforcement mechanism, then there's no incentive for Berkeley to ever provide captioning for these videos. They provide it for their students only because the ADA has strong enforcement powers like this. In the dream of edX's original mission--to provide Berkeley-quality education to everyone, free of charge--failure to caption those videos actually does represent discrimination against the hearing-impaired. So I think this is entirely reasonable.