I mean, yeah, he's been pretty clear that about that and the trademark complaint was awfully light on evidence of actual trademark issues. He doesn't like their business model, doesn't think they contribute enough upstream, etc.
But that's just not something you get to control when you license your software as GPLv2. Some people are gonna use it in ways you don't like.
He should have just done an marketing campaign about why you should host with Wordpress.com instead of WP Engine. Instead he's torched an insane amount of goodwill for seemingly no return.
WordPress.com isn't a good comparison to WP Engine. For starters, you can't install plugins, because you're renting out a single site on a multisite network and any custom plugin code would trivially violate the paper-thin isolation between tenants. WP Engine provides separately containerized servers and databases so you can do whatever.
It's like the difference between getting an account on a Mastodon instance versus a specialized Mastodon instance hoster.