If they ban Discord users, they would ban the vast majority of the North American (and probably European and Oceanic) user base. As in, literally everyone I know who plays the game has Discord, which they use for all sorts of things. Trying to make the argument "Discord is the sort of third party tool they are totally talking about" is either a.) being deliberately disingenuous which means you're not really trying to have a real conversation, or b.) you're trying to be hyperbolic to point out the vagueness of the ToS without realizing
everyone knows what kind of mods Yoshi-P is talking about.