The argument is entirely circular which is isn't surprising since "stupid" has a subjective component to it's semantics.
If supporting Trump is stupid then claiming that Trump supporters are stupid is loose truism, that is, so long as you also propose a single instance of "stupid" being sufficient to wholly categorize someone as "stupid" as opposed to someone who has done something "stupid."
The entire thing could not be more trite, but if there's one thing Flagpole loves more than himself it's arguing ridiculous semantics on a thesis that would be laughed at under even amateur scholarly scrutiny.