The law is not black-and-white. Absolutes like "Everyone can use your Trademark to identify the thing" don't fit in this context. Your reliance on Wikipedia to summarize a doctrine further demonstrates you don't have a firm grasp on the subject. Of course none on HN should listen to legal interpretations (including mine) because it's often not that simple. You can get a glimpse of the issue by reading this commentary from the American Bar: https://www.americanbar.org/groups/intellectual_property_law...

I think (and that's my opinion) that a jury would see that what wpengine is doing is not fair use and that their offering is creating confusion among consumers, but that's not for me (or you, or anyone else here on HN) to decide.