Israel can act with utter impunity as long as they’re backed by their big brother Uncle Sam.
What is to be done? In WW2, partisans helped stop the holocaust. Palestine is such a controlled area, far from the homes of most of us, it feels like there is no action that we can do to even slow the murder we are watching, while our governments cheer it on. So it's not surprising when people start shooting Israeli embassy staff or attacking anything connected to Israel they can find.
I don't think people want to sit back, this violence strikes a chord in anyone with empathy for innocent people. We can't directly stop the IDF, but there are people, companies and manufacturers in many countries that are supporting this. We need to stop the supply of weapons and components at their source, most of which comes from the US.