In our terms Voldemort is more like an ethno-nationalist taking advantage of a paralyzed, dying neoliberal structure and how it's already inherently racist. The wizards themselves live in a highly alienated liberal gerontocracy where nothing happens.
The closest thing to leftism is one book where Hermione tries to quite literally organize against actual slavery of elves and the other wizards treat her like a loudmouthed annoyance. Then they tell her elves actually enjoy being enslaved.