This isn't about doubling down on moral condemnation to squeeze every drop of righteousness out of the opportunity. It's about acknowledging the material consequences of large numbers of people making passive alliance with a smaller number of people who are actively fascist.
Because the dangerous thing about evil is not in how it expresses itself. It's in the creeping banality of how it actually achieves its aims.
And we may not have yet achieved the same gravity of events that Nazi Germany did, but there are enough similarities and dangerous potentials right now that the comparison is frighteningly relevant.
Think about how many people had a vague, uncomfortable idea that something bad was happening to the Jews, but didn't know much in the way of details or scope. So they found it easy to maintain their support for the Nazi party due to their stances on other issues. Or they bought into the anti-Jewish propaganda of the time and were simply content to know that something was being done about them, and blissfully spare themselves the details. Think about how many people participated directly in the cold-blood killing of Jews with their own hands in concentration camps vs how many likely didn't see themselves as murderers because all they did was show up to work every day to engage in all the other steps - transportation, paperwork, etc. But the whole process wouldn't have worked without their cooperation.
Now compare that to the immigrant concentration camps we have now, just as one example from our current political climate. They may not be extermination projects, but they're still large scale violation of human rights. The same principles are in effect. I don't believe that the majority of republican voters want things to be handled in specifically that mean a fashion. But I think the majority do carry anti-immigrant sentiments and want something to be done. They're probably content to spare themselves the details. Think about how many people show up to work every day knowing to some degree that their work is a part of the structural fabric that is doing some bad stuff... but they're not putting children in cages with their own hands, so it's easy enough to just keep showing up to work every day.
This is how it works. This is how actively evil people get everyone to work for them - through the auspices of law & order, through the normalization of their propaganda in public discourse as just another political opinion, and relying on the majority of participants and political allies being some degree of separation from the human suffering at the far end of what they collectively mechanize.
And you sure as hell don't stop it by refusing to talk about it for fear of offending people. If a decent person is accessory to the infliction of suffering, they should want to know about it.
Edit:
If it's valid to campaign against the right-half of the nation because things could end up like Nazi Germany, why aren't right-wingers equally valid with the extreme left / Soviet Union analogies?
EDIT: it's not that far fetched, given that both right and left wing dictatorships have been, and still are, widespread, and a vast number of people live under left-wing dictatorships even now. If one extreme should be feared, so should both, and a left-wing dictatorship is no more fanciful than a right-wing one.
We don't have dictatorship, but we do have the right doing its variety of really bad stuff anyway. We don't currently have the same on the left. So it's rather disingenuous compare call-outs of the left based on hypotheticals with call-outs of the right based on current realities.