Out of the loop

For the most part, they're not specifically supporting the Israeli government. They have endowment funds, which they invest in mutual funds and other such financial instruments, like everyone else. Those mutual funds, in turn, invest money in a huge array of different stocks, bonds, etc, generally with the goal of producing a decent return with a minimum amount of risk. Buried somewhere in that pile of investments are things like Israeli government bonds, shares in defense contractors, etc, because political priorities are not usually a factor in how mutual funds decide where to put their money.