Nobody wants to deny users anything. It is not really a question of pro or con accessibility despite the editorializing in the HN headline. Its a question of co

Nobody wants to deny users anything. It is not really a question of pro or con accessibility despite the editorializing in the HN headline. Its a question of content versus presentation. The first-frame preview is an artifact of the visual presentation of the video player and not relevant for non-sighted users, just as the colors used in css is not relevant for non-sighted users. The actual content is the video, and if you want to make that accessible you should follow the recommendations in the spec and "provide alternative media streams and/or to embed accessibility aids (such as caption or subtitle tracks, audio description tracks, or sign-language overlays) into their media streams".