My title asks why the US is funding 20% of Israel's military budget, but the truth is, I have the answer.
The US is outsourcing military might to Israel, so the Israel killing machine can refine their tools of death, and send what they have learned back to the United States (so the States can take over the world.)
What Trump has been doing lately in Gaza, the escalation of violence, is part of a master scheme by Trump, not only to destroy justice and peace in Gaza, it is a sharpening of weapons for his intent to destroy much of the rest of the world.
The Israeli/Palestinian Conflict seems to be a never ending dispute over a shrinking Gaza strip. The Palestinians in Gaza strip are locked there, much like a concentration camp. While doing their laundry, Palestinian people get struck by missiles and tank shards by Israelis, often women and children.
This is my simplified expression of a complicated issue of international conflict, but I think our mutual education is important and the media blackout on Gaza means that ordinary people need to be the ones discussing these issues of Peace and War.