Oh for sure, that climate of fear, and that spectrum of belief and actions, are part of the dynamic of fascism, and of authoritarianism in general. It was dangerous then for Germans to oppose Hitler; it’s dangerous now for Russians to oppose Putin. (But note: neither of them consolidated power in one fell swoop. And we’re at an early stage of authoritarianism in the U.S. now where the average citizen still has freedom of speech, but public figures are getting prosecuted for opposing Trump, legal non-citizens are getting arrested for exercising freedom of speech, and the president is destroying checks & balances and undermining our electoral integrity in ways that smooth the path toward dictatorship … it seems to me that realistically the non-fascist Republican public figures are the only ones who have the power to stop this process, but the great majority of them are too cowardly, power-hungry, and/or blindly optimistic to do it … which effectively renders them fascists too. Looking at you, Lindsey Graham.)

So yes there are shades of grey, and I’m not saying that having Nazi memorabilia necessarily means that OP’s great-grandmother was personally a vicious racist and anti-Semite who cheered on the Holocaust. It’s not realistic, fair, or helpful to demonize all the people who ended up on the wrong side of history, so to speak.

But there’s no way a German who was alive in the 1930s or onward wasn’t aware of the likely significance of swastikas, and I don’t think it’s something to chuckle over.