That 4e had a strong combat engine isn't the claim. It had this. It's the claim it did only this, when it actually increased non combat tools and systems as well, and gave many robust tools for our of combat stuff. It did both. 4e went further than any other edition in putting tools in the hands of players to resolve non combat stuff and to provide clear frameworks to the GM for resolutions.
Now, if you wanted to keep the GM Say methods of prior and later editions for non combat things, then these systems had little value. But not being what you wanted doesn't remove them from actually being there. If you choose to not value them, then sure all that is left of 5e is combat stuff. But that's a choice to discard systems, not evidence that they weren't there. It's also the exact pattern of attack seen during the edition wars. I have little emotional weight here because I missed those wars and only learned about them later. But it is a patterned attack and one based on misrepresenting the system based on preference and ignoring what was actually there.