@kjr @LouisIngenthron @freemo This is a great summary. This makes the distinction in terminology, and the reasons for it, quite clear.

Since people just hating Jews, Arabs, and other Semitic language speakers/groups collectively purely on the basis of their linguistic/cultural affinity is probably not a thing that happens to any significant degree, and since when it comes to real world Nazis and other bigoted, racist asshats, anti-Semitism in practice is always targeted at a racial category designed to consist specifically of Jews in the broadest sense, I can see why the term has a *slightly* different sense than what one would expect from the prefix and original word alone.