I highly doubt that version is true, though he likes to repeat it. If he doesn't like WP Engine eating his market share while giving little back (they did give back, just apparently not enough, whatever that even means in a volunteer ran open source project) then he would've not responded by pulling his own contributions off of WP.org as well, stealing their plugins, banning their developers, and so forth. Like, what even is that? You don't want to play in my sandbox according the rules that I set so I won't play in my own sandbox either? Not to mention that if there's anyone doing monopolization in the WP world, it's Matt himself, by buying up basically every WP company there is.

His so-called "democratize publishing" persona is just a complete facade.