That overly reductive thinking can go back to the 80s before we had learned any lessons. There are degrees of trust. Binary thinking invites dramatic all or nothing failures.

And my point is that with HTML, there's always an extremely fine line between allowing "almost nothing" and "almost all of it" when it comes to sanitization. I'd love to live in a world where there are natural delineations of features that can safely be flipped on or off depending on how much control you want to give the source over the content, but in practice, there are dozens of HTML/CSS features (including everything in the linked article) that do wacky stuff that can cross over the lines.