"You could also have mentioned that almost a half million Americans died fighting fascism in WWII. And yet this same vermin is allowed to thrive in the USA. Why?"

I'm thinking you don't know that the Nazis themselves referred to those they hated as "vermin." Congratulations, you have (perhaps unwittingly) stooped to their level.

It's better to say that millions of people died defending democracy, rather than that they were trying to defeat something else. 

Democracy, as an ideal, is worth defending. And one of the principles in democracy is that we we tolerate all points of view within the limit of the law. It's not against the law, either in the USA or in Canada, to hold white supremacist, neo-Nazi or other extreme right-wing views. We don't tolerate those views because we condone them, we tolerate them because we're confident we can resist them. The same is true of extremism in any other form.