Because Israel is more profitable of course. Whatever "justifications" the US uses for war are always just excuses to earn the ruling capitalist class more profit.
Capitalism just follows the money. Though if there's enough protests and riots at home, the cost of managing that would outweigh the profit of genocoding native Palestinians.
Strengthening Israel's military also gives them more power and influence over the oil in the middle east, and keeps the countries from uniting against the imperial core.