Because everyone always compares whoever they don't like to Hitler. He's there on the last page of "The Little Book of Rhetoric for Weak Thinkers", and sooner or later everybody goes there.
I have no sympathy for Perkins, his tin-eared similes or his John Galt-by-way-of Marie Antoinette rhetorical snow-job. Nevertheless, I have to say that I've heard the Hitler analogy made at least as often by the downtrodden and leftists as by conservatives and members of the elite.
You know who else used to compare people he didn't agree with to Adolf Hitler? Adolf Hitler, that's who!
Actually, he probably didn't. Which makes him just about the only one.