just to pick a minor point here: it is important.

Hammas [very very stupidly] fired rockets over the border because they believed this would give them political leverage to demand Israel loosen off the border clampdown to led food and aid through. Bear in mind that Gaza is surrounded on all sides by Israel and the sea, and gets pretty much everything via the Israeli border. Israel has been a bit crappy with regards to letting stuff through.
In the early stages of the conflict, there were 3 Israeli deaths. There were thousands of Palestinian deaths, mostly civilian.

Now, a question. If you owned a mansion that was invaded by some other people who eventually forced you to live in a corridor and kept all the doors locked, so you had to ask for their permission to do anything *except* just stay quietly in the corridor, what would you do?

Would you quietly accept your new corridor existence and live peacefully, or would you fight back with every tool you could possibly find? That is the plight of the Palestinians. Israel is, in fact, the invading force. It just happens to have backup from some of the richest and most powerful people in the world who are mostly American.