Yes, I think even people not well acquainted with all the history could agree that killing civilians is really not acceptable in any context.

In regards to Palestine and Hamas, some food for thought is that Hamas was elected in 2006, and the median age in Gaza is 18 years old. The vast majority of people in Gaza weren't even alive or old enough to cast a vote for Hamas the last time the opportunity was there. Which I think centers the most important part of the conflict to understand; the majority of the people dying, whether they're Palestinian or Israeli, should not be having to pay the price that they're paying, they're just people trying to live their lives.

You might be interested in this overview of the situation in Palestine/Israel by David Dole, I think he does a good job of framing it all with a humanitarian perspective that clarifies some of the moral confusion that plagues this topic for so many. What many don't understand is that most of the Israelis and Palestinians don't want the situation to be this way, it's smaller groups of loud extremists that keep pushing violence.