Democrats! That is who and what is behind the Anti-Israel sentiment in Congress. Just like they were for segregation before anti-segregation became popular, they are for taking away military and defensive funding from the Jewish people. Just look at the people voting against it like Alexandria Ocasio-Cortez,Ilhan Omar, etc. It is part of the democratic platform until it starts to hurt them. Then it will stop.
Though I'd agree, there's no political capital there since the Iron Dome aid was passed in a stand alone bill in the House, but blocked by a Republican in the Senate.