Haven't ya heard? It's not what the filter, er mask does, it's what it is. It's an assault on their freedums by the radical libs. "Those lowdown commie lib Democrat radicals can't be tellin' us what to do! Even if it is for our own good

". To accept masking up would mean accepting the fact that they've swallowed the lies hook, line and sinker. Accepting that they've been bamboozled would FUBAR their entire belief system.
It's easier to con someone than to convince them that they've been conned.