

Yes, it’s the red scare, but most translations of Karl Marx do use the word “socialism” for the state he described as a precursor to capitalism. And the name of the Russian communist federation was generally translated as “Union of Soviet Socialist Republics.”
Note that most self-described “socialists” aren’t literally suggesting we ban the ownership class, declare the value of all stocks to be $0, and force every corporation to operate as employee-owned collectives. They’re usually arguing for things like “expand our old-age health-insurance program to just cover everyone” or “make the city buses not charge a per-ride usage fee.”
The hate against “socialism” is precisely because Karl Marx and some 20th century communists used it to mean something different, and then the right wing of United States used that label to try and smear every social program since the ban of slavery. Now we have two entirely different and incompatible meanings, and both a lot of bad-faith actors who intentionally conflate the two and a bunch of good-faith actors who aren’t even aware there’s a difference.