Well, now balance that against the rest of the upsides they present, like the new UX not being to merely revert the changes that you spent the weekend writing.
Let's stop acting like just because we can think of one downside that we can ignore the rest of the trade-offs. Btw this is a trade-off they already mentioned in TFA rehashed by an HN comment for some reason.
Because HN commenters always feel like they know better and like to talk down on any changes even when they have no context for why the decision was made.
Is higher friction a bad thing though? This is web standards documentation, not Wikipedia; once a document is finished, it'll be a lot more static. I can imagine they've had edit wars (another commenter mentioned it), abuse, etc, whereas with a GH workflow there's a better review process involved.