They don't care. They are so deep in their cult, nothing can pull them out. If tomorrow, Trump came out, completely lucid, and admitted everything was a hoax, his supporters would just shift to another cult leader.
Also, at one point, they referred to themselves as Centipedes. They probably got tricked into it, but they still did it proudly. Calling them Magats isn't much different.
Can you tell me how to say that differently? If people from America are Americans, people who believe in Catholicism are Catholics, people who believe in MAGA are what exactly? It isn't Republican, because they are a subgroup, like Jacobites. It isn't to dehumanize them, it is just what they would be called from what I would expect.
Maggots has a different spelling, which is what i know you are referring to, but maybe they should have choose a different name/slogan to go under