You are free to say that a cat means cats and dogs till the cows come home but you would be wrong.
Definitions of words are definitions even if you think the definitions don't make sense.
You are free to lobby the dictionary publishers.
But it won't work because your proposed definition of antisemitism is idiotic.
It would make it into a useless word. Not sure what agenda you have that you are so passionate about this. My experience is that it comes from people who want to deny antisemitism is widespread or serious,
There are already ways to describe hatred of Arabs, hatred of Muslims, etc.