Yeah I think it’s quite a leap to go from “html is successful because it’s fault tolerant” to “this applies to communities as well”.

There’s obviously a case to be made for both, but they’re independent and unrelated.

For me, it's an especially bad argument because the sloppy nature of HTML parsing is NOT a virtue... it's a source of bugs, vulnerabilities, and incompatibilities that provides (yet another) technical moat for existing web browsers. It's a huge tragedy that HTML5 beat XHTML.