Antisemitism is a form of prejudice against Jewish people based PURELY on their RELIGIOUS beliefs and/or ETHNIC identity.
It goes back thousands of years and is steeped in cruel bias and harmful stereotypes or outright hostility. It's bigotted and created lots of tropes.
Antizionism is the criticism of the POLITICAL ideology of Zionism. This does not inherently involve prejudice against Jewish people, but it criticizes and focuses on political and territorial disputes and military practices, and rights of Palestinians.
Basically one attacks an identify the other a political stance.
I can't ignore that yes some may use antizionism to cover up anti-Semitism, but it is also very dangerous to unfairly label anyone with legitimate criticism of Israeli policies as antisemtic as that deflects or shuts down debate.
It is antisemitic to say "all Jews are responsible for what is going on in Israel"
but similarly and this is why we cannot conflate, it is antisemitic to say "Criticising Israel means you are attacking ALL Jews"
Incidentally, many CHRISTIAN Zionists (quite a few who are OPENLY antisemitic) strongly support Israeli govt policies and actions, and heavily fund them, but for very insidious reasons; using Jewish people as cannon fodder for the End Times- they're happy to see the Jewish people burn or convert. How is that not antisemitic?? Blows my mind how that little detail gets brushed over in debate.
Yet, it is the Palestinians, who have lived amongst Jewish people for millennia, in peace, that are the crazy ones that "want to wipe the Jews off the map"?????