[But...]I'm a little bummed that the first explicitly Judaism-focused story (And possibly only the second and third Jewish characters? I don't know of any others except for Rufus.) had to be about Nazis. There are plenty of other conflicts to base a story around, ones far more complex than the black and white nature of Nazis v. Jews.* Not that I'm complaining about a story that paints the Jews as good people, but Holocaust stories tend to also paint Jews as victims.
Not that this one does! At least, not entirely - the rabbi and their people do require protection, and without his instruction manual Aaron is pretty helpless, but that's a function of being human against a magically powered foe. The golem (And by the way: !!! The golem! How awesome was he?) was created as a method of protection, to balance out that helplessness.
Which leads to my second point of disappointment with the episode... which is more of a general disappointment with the show? The second the immediate threat of undead Nazi necromancer had been dealt with (by the golem, at that), Sam and Dean immediately sought out a way to destroy the thing.
Why? Literally its only purpose is to protect Jews. What is so terrible about that, I ask you?
If their reasoning had been framed as "you don't know how to control it, and someone with darker motives could take it from you," then I might understand it. That is, as shown by the episode, a legitimate concern! But nope, it was just "Look at this big muscular guy, he threw Dean into a car and was totally unaffected by this knife, we have to kill him."
I'm glad they give up on that in the end, and that Aaron and his golem set out to find the rest of those undead Nazi necromancers, but the reflex to find a way to kill anything and everything nonhuman still unsettles me.
The last thing that bothered me was the flirting moment in the bar. I enjoyed it at first - canon gay Jew! Dean being super awkward about being attractive to a guy! It fueled a lot of closeted!bi!Dean headcanons I have. But later Aaron reveals that he only flirted with Dean to distract him from the fact that he was following him. It makes the moment come off as a little homophobic (assuming that a guy flirting with Dean would rattle him)**, and on a metatextual level, by teasing viewers with the possibility of a guy being interested in Dean and then taking that away and making it a joke, as queerbaiting. Which I'm never a fan of.
*Note to self: How awesome would a Supernatural take on the Wandering Jew be? ...if they remembered that the guy would have to be Mizrahi and not Ashkenazi. Man, though, I'd love to put that guy and Cas in a room together, that'd be something.
**Yeah, you can argue that Aaron wasn't trying to rattle Dean, and just thought "being romantically interested" was a good excuse for following Dean around, but. It was still the first thought that came to mind when Aaron revealed he'd been faking it.