Well, with this guy we are talking insane and not necessarily Stupid. Generally, if all he were was crazy his ability or knack to inflict other harm on himself or those around him might limited he might not rate that high.
But if he is some SJW in their service of his madness his Stupid Class could easily go much higher, especially as he joined groups and collectively they represented a more profound threat to wellbeing than just the odd nutter whose lopped off his wiener.
“My wifes’ a Tard,
She’s a Pilot now!”
Idiocracy needed a Tard Scale.