Seems like those 'other' groups were generally defined by biological characteristics, not ideologies, no? I guess the 'anti-communist' movement would fall under ideology, not biology, but the majority of examples I can think of that you're alluding to have to do with biology, no?
No. "Jewish" isn't biological, although there is some correlation, and America's red scare was soundly ideological.
I would think that's your 'red scare' unless you're talking about something else.
The "jewish" one - thinking specifically of ww2 - it definitely was more of a biological component, as "how much" you were jewish, and from what lineage, made a difference. "jewish" is both cultural and may have a racial/biological component (imu).
Quick question: does anyone defending the racists, sexists, homophobes, etc., have any other argument than "SLIPPERY SLOPE!!!"?
Once you accept a moral system that justifies no longer treating human beings as people, you've allowed yourself a system that can justify anything. Look at every genocide of the past century; they all start with classifying a group of people as sub-human and worthy of discrimination.
That is a view to be fought, not descended to.
[1] https://en.wikipedia.org/wiki/Categorical_imperative#The_Sec...