To be clear he didn't say this right?

kramer looming in the wings, eyes glowing red, vibrating like a cell phone stuck in an emergency alert pattern

This is just a bit from “To Be or not to be”. (1942, but I know the Mel Brooks Remake from 1983), and Jerry is unaware the character he’s emulating is a Nazi commandant.

“I hear they call you concentration camp Seinfeld”

“Well, we do the concentrating and they do the camping”

They did often joke about Jerry being a great Nazi.