If Israel supports Ukraine, it will undermine the claim on occupied territories and Jerusalem. If Israel supports Russia, it will risk to lose the support of USA (like Iraq after being ally of USA against Iran). Also there is significant amount of Russian agents in Israeli political landscape (basically, all Russian speaking politicians).
No one buys this claim who is important, not the U.S, not the E.U, not China and not even Russia. Israel knows this very well, so I doubt that's the reason. Even many Israelis probably don't buy into this claim, they want to hold on to the territories due to security reasons and what happened after the Gaza withdrawal.
> Also there is significant amount of Russian agents in Israeli political landscape
Significant amount? Do you have some data to support this? You're also suggesting they are all Putin supporters which sounds like a reach to me. Many of them came to Israel not loving the Russian totalitarian experience.
Literally, LOL.
>Also there is significant amount of Russian agents in Israeli political landscape (basically, all Russian speaking politicians).
You seems to conflate russian speaking with russians. I lived in Israel for 25 years, and now I tried to recalled how many people from Russia proper I know, and I cant even reach count of 5. Besides this, russian speaking politicians (all 3 or 5 of them ? most if not all of them not from russia) have no weight in Israel politics, especially in such a strategic decisions. As good example will be a strategic decision of smaller degree, when Gazprom wanted to get into partnerships in gas drilling companies in Israel but was booted out.