I appreciate your train of thought on the MCU category only being applied to characters with the tag in-game, but I had added those categories as previously, each Champion had a category relating to their origin. I was under the impression that not all tags were being put in categories, seeing as how only a small selection of pages have all of their tags in their categories, but I guess this method will stick for now.
I saw this as being the Marvel: Contest of Champions wiki, and so for organizational purposes, tagging champions with categories is really helpful for in-game purposes as opposed to comic book or movie purposes. The only reason that specific Champions got categorized as MCU Champions is because that's how they're referred to in the "Gwenpool Goes to the Movies" event storyline. If people want to know what Champions that MCOC considers MCU Champions, tagging every Champion that has appeared in a Marvel-related television show or movie muddies those waters, don't you think?