I’m pro-Palestine all day but I don’t like this line of questioning. The only reason I see to make this argument is to try to erase the very real horrors the Jewish people survived.
However debate lords are still gonna want an answer (not trying to imply you are one). If I had to respond I would say:
English is a living language. The definition of words is determined by how we use them. Think of “literally”. It meant one thing but it was so misused that the definition had to change because the common use was completely disconnected from the textbook definition.
The words “Semitic” and “anti-semitic” did not come into existence at the same time, similar to matter and Antimatter. “Anti-Semitic” is specifically “anti-Jewish” because that how the phrase was used.
It’s not a word whose definition comes from the literal sum of its parts, it refers to a specific phenomenon.