John Kerry is right about one thing. Assad is like Hitler. It's a solid comparison. One was a murdery sociopath power-hungry torturer. The other is as well. Now if you want to compare details and say one killed millions, as opposed to thousands, go ahead, but it's not an ethical comparison. It's a comparison of circumstances and strategy. It may or may not be the case that Assad, in Hitler's shoes (a mostly nonsensical hypothetical), would have destroyed just as many human lives as Hitler did. Who knows? But you're just making stuff up if you imagine that he wouldn't have and this because he's less evil, or would have shown restraint, or some other thingsweassociatewithpeoplewelike type bullshit. What we do know is that both belong to the category "murdery sociopath power-hungry torturer," and that's far more important than any differences you might find between them.
Kerry's mistake, if you can call it that, is in failing to mention that he, Kerry, and his buddy Obama, are also murdery sociopath power-hungry torturers. Monsters, more than anyone, misunderstand themselves, for good reason.
I've had the same back-and-forth with an Obama apologist several times. Obama is, uh, kinda like Hitler, I say, in my Larry David voice, but not really because I type it. You're just being dramatic, rhetorical sleight of hand, whatever, he says. Well we can go with Pol Pot or Stalin, if you'd like, I say, as long as it's someone you recognize as a murdery sociopath power-hungry torture lover. But I'm not letting you off the hook with Churchill or Theodore Roosevelt because, in spite of the fact that they were every bit the murdery sociopath power-hungry torturers as your recognized evildoers, you have them filed away under us/family/good guys with all criticisms passing over "what kind of person does this sort of thing?" as if it weren't there and proceeding directly to "the imperfections of good guys." If I let you compare Obama to Churchill, you're in your apologist comfort zone. You don't even mind, because you really don't understand that Churchill was a...you know. You're gonna use a bullshit interpretation of history as a frame of reference to justify contemporary bullshit. "Oh, Obama is like that good guy with flaws? OK, maybe I can see that, convince me," he wants to say. No, my point is that Obama is like a guy whose every day revolves around destroying lives. Who wakes up, has his coffee, pats his ladyfriend lovingly on the head, and destroys lives. Like, for example, Hitler.
My point is that you're making a massive category error, again and again, and Hitler is the corrective. If you actually understood the very available facts of Churchill's life, I'd simply make that comparison, though I wouldn't need to, because you'd already have understood. But you don't, so in spite of the too frequent rhetorical abuse of "Hitler!" in contemporary political discussions by people like John Kerry, and with due caveats for specific historical circumstantial differences (Obama was elected! So was Hitler! He was? What? Who cares?), I am very much above Godwin's law.