Access to online content by those with disabilities is going to be an ongoing trend. PornHub points out that they do have a closed captioning section. My guess is the videos he wants to watch aren't in the closed captioning section. He probably wants all videos to be eligible for closed captioning. Could be another revenue stream for PornHub to have an advertiser sponsor closed captioning.

I think it is wise to add accessibility functionality to large trafficked sites like that so that all visitors regardless of disability can enjoy the content. You're enlarging your pool of potential premium users that way. Lastly, its really hard for me to feel sorry for PornHub (MindGeek) who built their empire by pirating pay content and destroying the adult industry so they could take it over...