I’m referring to the fact that “anti” and “semitism” are existing complete words. Every other example of a word given the “anti” prefix that i can think of is very clearly meaning, the opposite or against the existing definition of the word.

Antidisestablishmentarianism Antisocial Anticlimactic Antiacidemic Antibacterial Antifreeze Antihero Antihistamine

Hammer in your comment is a poor example, because hammer is its own word, despite the first three letters happening to be an existing other word. Antisemitism is clearly anti and semitism.

What’s annoying, is since this term was coined (as you said, in germany), it was purely a dog whistle for jew hatred.

Wikipedia:

The compound word antisemitismus was first used in print in Germany in 1879[19] as a “scientific-sounding term” for Judenhass (lit. ‘Jew-hatred’),[20] and it has since been used to refer to anti-Jewish sentiment alone.[21][22][23] Due to the root word Semite, the term is sometimes subject to an etymological fallacy whereby it is incorrectly assumed to apply to racist hatred directed at “Semitic people”, in spite of this being an obsolete racial concept.[23]

We need to let language do its thing, and adjust the meaning of this word to mean what it appears to mean, not some wink wink nudge nudge version you have to know ahead of time.