Most of Tarantinos fans don't understand this. And its frustrating
At its basic level its nazi torture porn. But at a deeper level it's about how easy it Is to fall into a hive and start wishing death on everyone (like the Nazis)
Of course everyone mentions the theater scene as a beautiful meta moment (Nazis watching the film - us watching the film) but few people seem to notice Hitler says the exact same words as Aldo (this Is your best work yet) because the reality is there actually pretty similar. There both barbaric and cruel. Only working toward extermination. There the same guy.
Of course I could mention the soldier who died because he didn't want to give up German soldiers or the father who begged not to be killed before being gunned down.
This article covers most of what I think Tarantino was doing
https://www.google.com/amp/s/m.huffpost.com/us/entry/270952/amp
Its completely obvious to me what the attention of it all was. Thats why it's sooo frustrating trying to watch this with other people. They don't get the actual message of the movie is the same as that old Twilight Zone episode. People are alike all over