Subject: Re: ethnic v religious v ???
"Anti-semitic", strictly speaking, should be discrimination against Semitic people.

Only if you're an inveterate linguistic prescriptivist.

The etymology of the term anti-semitism derives from academic disputes between racists and critics within Germany and Austria in the late 1800's. But almost immediately after being coined, it quickly assumed its current meaning as a synonym for prejudice against Jews. Not "semites" - an even-then obscure and now largely obsolete linguistic category. Jews.

The "real" meaning of a word can change over time. Awful and awesome used to be synonyms - now they're antonyms (to a first approximation).

If you're anti-semitic, it means you are prejudiced against Jews. Not semites, not other people who speak semitic languages or who are descended from other groups that speak semitic languages. Jews. That's what the word means.