There are many possibilities. The conspiracy theorists like to talk about how the people pushing the "pro Israel" actions in the U.S. are more loyal to Israel than they are to the US and so their end goal is to make Israel a regional superpower in the Middle East and to them in the end, it doesn't matter what happens to the US. I mean if you are loyal to Israel and not the US I could see this. Each country acts in their own interests and these people have been able to exploit the weakness of money in politics for their benefit. I personally don't fully buy that, but that's one theory.
Another theory is that the leadership in Israel is not really thinking long term. They are suffering from the same issues that other poor leaders like Trump are suffering from. They're just looking at themselves and what benefits them in the short term, so the moves that they're making are beneficial in the short term but very detrimental in the long term.
It's possible that they think that the US decline is inevitable due to uncontrolled spending, the decline in development in its people and other issues etc. and so they are grabbing as much as they can before it collapses and then afterwards they align with the next superpower there have been some moves in that direction to open up to China although small. Its a risky move because China may not treat them anywhere near as well so Israel has to work harder to earn its seat at the table but if the US decline is out of their full control then the next best move is to grab as much as you can before it comes crashing down and then move on.