There has to be a middle ground though. For instance, I am definitely the opposite; I would feel as the site would be less usable to me if it just ran once and I had to reload the page or spam click replay if I wanted to see the animation again. I'd imagine people who are slow readers or with dyslexia would feel the same, and would make similar aurguement that you are making that them auto playing the animation assuming everyone had same reading speed when the animation is in focus are not taking thier cohort in consideration due to the small size of the group. I am sure that there are some colorblindness condition that would find the colors of the site difficult to distinguish as well. I would be be more emphatic to your view point if this was a school/employment/healthcare/goverment document, but it isnt realistic to say a primarily artistic/design project has to cater to everyone's specific accessibility concerns.