The submission title, "Editor of HTML5 (Ian Hickson) shows poor understanding of accessibility", is unnecessarily personalizing, editorializing, and polarizing.<p>It's likely Hickson's questions, and reluctance to accept a specific proposal without more data, are a matter of seeking understanding, and working through different ideas about what the proper significance and use of a 'poster' image for video might be.<p>(A better title might be: "Debating fine points of HTML5 accessibility: video 'poster' images and alt taxt".)