As a child, I was actually interested it history; and, as an edgelord, especially interested in gruesome totalitarian regimes. I played a lot of war-themed games, inevitably many had Nazis. Of course the games aren't usually historically accurate but led me to read more about the actual events.

I had seen the totenkopf decades ago but did not know this was a Nazi symbol until I saw the Mitchell & Webb skit about ten years ago. If you asked me for Nazi logos, I would have come up with the swastika, the SS lightning bolts, and the Adler (which is used by the good guys in the Contra video game series).

(album cover of Singles 1-12 by Melvins, 1997)

Can confirm, Americans stupid; we were never shown this symbol and now our country is infested with fascists.