I see this kind of thing all the time with third-party WordPress and WooCommerce plugins, it seems like WP Engine managed to generate enough perceived consumer

I see this kind of thing all the time with third-party WordPress and WooCommerce plugins, it seems like WP Engine managed to generate enough perceived consumer confusion (looking at the exhibits, frequently in the form of support requests from WP Engine customers posted to official WordPress channels), such that Automattic felt compelled to do something about it. That said, from what I can tell, there are dozens of similarly branded "WP [something]" plugins that engage in a lot of the same "brand-borrowing"--there's probably an actual term for this, but deliberately leaving one's association with WordPress ambiguous to leave open the interpretation that your plugin is more official than it is. EDIT: changed consumer confusion from "obvious" to "perceived"--I have no idea whether these examples were obvious, and it would likely depend on your own perceptions.