The whole affair- or rather, the light in which Mullenweg's own conduct casts him and his company- has a stink about it I can only describe as Musk-esque (no pun intended).
Even if the original complaint- that WP Engine were profiting off Wordpress while giving nothing back- was legit, the way Mullenweg has gone about it isn't.
Blocking access to WP's facilities may be legal, but using it as a blatantly selective weapon against a rival risks seriously poisoning the well of non-partisan trust the "community" took for granted until now, and has probably already done so.
Using a dubious trademark dispute they had no problem with until they wanted to use that to force WPEngine to contribute is even less justifiable.
It's also clear that there's now a blurring of the lines and conflict of interest between the Wordpress Foundation nonprofit and Automattic with Mullenweg arguably leveraging his involvement in the former.
As I said, even if the original criticism of WPEngine was legit, Mullenweg's response isn't, and he's already well into into untrustworthy douchebag techbro territory.