"Criticism of supporters of the Israeli regime = antisemitism every time"

That is a ridiculous statement. Who in their right mind can condone certain actions of the Israeli Government.
They are in breach of International law with their continued occupation of the Golan Heights.
There continued attacks on Syria are acts of war.
Their threatening to destroy the latest generation Russian air defences if installed in Syria.
Their heavy handed actions in Gaza
Their continued defiance of UN resolutions.
Unfortunately they are an out of control outlaw state relying on the US to constantly back them up.
When the bullies finally get a bloody nose hopefully the rest of the world will keep out and then maybe a permanent peace in the Middle East can be negotiated.