The crazy part isn't that people want to be able to disable that. The crazy part is that they want to pay to disable them...
No you guys, that should just be an option, no questions asked. Included in the options menu for... Well, whatever the asking price of the base game is. Also known as included in the base game.
I really dislike being reductive so take what I say with a grain of salt:
I am not surprised that the people who regularly buy the COD series with all of it's monetary practices for the past decade are asking to buy a feature. They'd be more shocked if you could features/updates/qol without buying it. Habituation, de-sensitisation, whatever - they're the whales that fuel the decline in AAA games.
People are offering to pay as a hyperbole to try to tell Activision how much they want to disable the skins. Nobody actually is willing to pay extra for that. Its like dangling a carrot in front of a corporations face.
"We want to do X so badly, we are willing to pay for it," which translates to " We want to do X so badly, we are willing to do the last possible option that we want in order to be able to do X."
People are offering to pay for it because they understand that providing that feature would potentially cause lost revenue for Call of Duty, since (theoretically) players are buying skins so other players can see them.
I imagine there are a lot of potential solutions (I can think of a few at least) but Activision probably think the lowest risk is to do nothing.