The video in question, the video under "ereader on steroids", appears to be sped up, my guess is because the purpose of the video is to summarize the functionality. A "3x" label would be nice, but let's not jump to accusations! That video isn't at all in a context where it seems likely meant to mislead. You can view other videos on that page that are in 1x.
Assuming you're talking about the link to a video posted by another commenter further down ( https://news.ycombinator.com/user?id=mikhailt ), that video was posted out of context. There are a lot of other videos on that documentation page which are not sped up. See here: https://daylightco.gorgias.help/en-US#article-493382
The video in question, the video under "ereader on steroids", appears to be sped up, my guess is because the purpose of the video is to summarize the functionality. A "3x" label would be nice, but let's not jump to accusations! That video isn't at all in a context where it seems likely meant to mislead. You can view other videos on that page that are in 1x.