Is Matt Mullenweg defending WordPress or sabotaging it?

Mullenweg just keeps digging. He is the only person I have ever seen interacting in such a petty manner that he made a company backed by Private Equity look like a victim. If Trademark was the issue, why did it take him over a decade ? Why is he not going after all the other gazillion WP providers that use similar phrase on their website ? We all know the answer. The only company (WP Engine) that beat his for profit company (wordpress.com). He is just salty.

Well charitably I would suspect that for the first question, he probably didn't want to rock the open source community too much. Look at the trouble the rust foundation got into for trademark enforcement, and it hasn't really been a decade. In general, there's no good time to start flexing on your trademark.

For your second question, Matt claims that it's partly because WP engine disabled core features of WordPress. I can imagine a world where you are inundated with complaints that your software doesn't do X basic thing (because the top provider has disabled it) but ITS BEEN THERE THIS WHOLE FUCKING TIME TIME STOP COMPLAINING (put a smile on and explain calmly). You get my point. And then you snap.

No idea if that's what is in his mind but I have some sympathy for Matt. In principle. (This is me steelmanning Matt)

Disabling/limiting revisions is built in to WordPress.

All WP Engine did is add:

define( 'WP_POST_REVISIONS', false );

to their configs.

Even if they had literally disabled 80% of the functionality of wordpress, would that still be the concern of anyone other than WP Engine and their customers?

Why would anyone using open source software be required to use 100% of the functionality that the software is capable of providing?

Trademark is exactly supposed to protect the reputation of WordPress. If people confuse WPEngine for WordPress, and assume if WPEngine doesn't have it, WordPress doesn't then that's damaging to WordPress. Except that WordPress doesn't (and legally can't) claim "WP". I'd be frustrated.

This is like asking what is it a concern of McDonald's if you open up your own restaurant call McDonald in your town and make it a dump

If McDonalds for years had a page on their website that said “you can use McD any way you want, it isn’t trademarked”, that would be a good analogy.