That's eleven men.
This is bad and I don't want to justify or defend it. But this does not indicate mass executions of civilians as policy. It could well be a platoon leader who overstepped authority.
As the report states, the UN is calling for a formal investigation. As well they should.
When I responded, the submission went to the World Socialist Web Site. I linked above to the actual report. If you read the actual report, you see that eleven civilians were murdered. And that's terrible. The report rightly calls for an investigation.
You ask, what is a mass execution or massacre? Well, what happened here is unlawful killings. It's a massacre. But my point was that an investigation was needed to determine if these killings were the result of Israeli policy or an event on the ground out of the hands of actual policymakers. Which would look something a whole lot more like the Katyn Massacre, where Soviet troops murdered 22,000 people in Poland during WWII.
https://en.wikipedia.org/wiki/Katyn_massacre
This doesn't diminish those eleven lives. But that's the difference between state policy and a military commander gone rogue.