Well, in terms of law, international law such as the united nations charter that the us and israel have both signed onto and both have rejected/vetoed numerous resolutions attempting to hold israel and the us to international law. You could also look at the universal declaration of human rights.

Seems like that first sentence is leaving quite a bit out.

Yes both sides have lost many lives, however the lives lost on the Palestinian side are many times that of the Israeli side.

Yes Israel has a right to respond to attacks. However, does it have a right to respond by inflicting collective punishment on a civilian population?

By the way, that is one case of a violation of international law. Palestinians are very clearly "protected persons" under the Geneva Convention. (en.wikipedia.org/wiki/Fourth_Geneva_Convention). There are many other cases as well.

Your last question is an important one. Personally, I don't support the Hamas government, my solidarity is with the people in Palestine and Israel working for peace in spite of their governments. However, non-support of Hamas doesn't mean that I then support whatever action the Israeli government takes. Also, it makes much more sense for people in the US to discuss Israel's actions when we are funding with billions of dollars.