Why not. If we had multiplayer compatible local-only mods ("themes"), that would not only allow the color blind to enhance usability of their game while still being able to participate in vanilla multiplayer.
It would also allow people with all sorts of other vision-related problems to do so. There could be low/high contrast themes, night/day mode themes, indeed a theme for each colorblindness variant - and themes featuring different sounds as well.
It would also allow for non-disability-related themes. As an example, there could be a rust (like in iron oxide, not the game) theme, wich makes everything look more rusted.
Sure, the base game needs to be good for the majority of players. But 8%, wich aren't even a homogenous group, aren't the majority.
With theming that wouldn't matter. They would still get a game wich works well for them while it also is looking as intended to the non-colorblind participants of the same multiplayer game.