Were they pro- or anti- poor? (That clip suggests anti-, but I always thought of the Stooges as a lower class phenomenon.)

Well if you think about it, prewar it was unlikely that anyone poor could afford a TV, so pandering to poor people while most of the viewers are rich wouldn't work.

I'm no expert, but during the depression years they seem mor ecomplex, on one hand the audience was more likely to be upper class simply because of the economic situation making movies less accessible to a lower class audience, but on the other hand the plot arcs almost invariably involve the working-class Stooges invading high society or elite professions like medicine and academia, outwitting and humiliating them, and then narrowly escaping (usually), thereby playing to class anxieties on both sides but to my mind focusing more on working class frustration.

In the postwar shorts like this one, they were more just lovable, low-class buffoons and by the 50s they were mainly doing fantasy scenarios for children, usually cowboy-and-Indian type stuff and rehash haunted house routines, and class was less overtly in play.

They didn't reach television until very close to the end of their careers and I'm not sure how much impact it had.