1. Many of these hate groups outright use nazi iconography and self identify as nazis and talk about how much they love hitler.
2. I honestly don't care if the (increasingly passed on due to age) generation that directly experienced WW2 and the events leading up to it are grumpy that the term "nazi" is being used again. I very much DO care about the current world that is dealing with a global resurgence of nazis/"nazis". History should be learned from and if your only takeaway from WW2 was "German parties that identify as Socialists are bad" then you missed the point.

Just to expand on the last bit some more: World War 2 was (approximately) the early 1940s. I forget what the official dates are but it wasn't a bubble and there was lead up and ramp down afterwards.

1940 was 85 years ago. So for someone to be a child with meaningful memories of the time puts them closer to 95 right now. For someone to have actively fought (late teens), that gets to 100. This is WHY basically any reputable WW2 historian will have some variation of "I was fortunate enough to talk to so and so before they passed" because... the odds are very "good" they did.

Which contributes a lot towards why we see such a resurgence. All the olds who actually experienced it are dead and not around to say "the fuck is wrong with you".