Quite a stretch to think that's the issue at hand here.
It was a dude LARPing as Hitler as part of a serious debate
Whitewashing/forgetting history is folks who make claims like "RACISM DOESN'T EXIST".
A "serious debate" opened by a teenager gleefully proclaiming "I'm quite drunk" - so much so he was being unable to properly introduce the guest speaker? "LARPing" by adopting the character whose viewpoint he was demonstrating? Really?