Actually what Hitler did was substantially worse than what Assad did. Assad was killing people in revolt against him, and the babies were, to use a favorite American military term “collateral damage.” He would probably have preferred no babies were killed, or at most did not care. Hitler went way out of his way to exterminate what he hoped would be millions of people, most because they were Jewish and no matter what their age. Before killing them he used many as slaves.
As for the “his own people” crap- many were German citizens and had been for generations.
But the vileness of the American right has never been much tempered by facts or morality.