Up until a couple of days ago, when Matt retroactively changed (which is going to be hard to make stick) the trademark license explicitly permitted the use of "WP" by anyone and everyone.
The trademark license also cannot prohibit nominative usage - that's protected. If you actually, factually offer WordPress hosting, you can say so, in those exact words. You may need to call out somewhere (and WPEngine does) "WordPress is a trademark of the WPF", but no license can prohibit you saying so. What they can't (but don't) say, is anything that implies that they are WordPress - which is exactly why Matt is trying to make some big deal in his head that "my mom thought they were us" (while ignoring the elephant in the room of "Well, wordpress.COM isn't WordPress, either, it's just a licensee", because of course, nobody could be confused by that).
I was only responding to the statement about the GPL, which simply does not apply to this situation, since it is a trademark dispute and not a copyright dispute.
I wasn't expressing an opinion one way or the other, regarding the validity of the trademark infringement.