The people in question were attacked because they were "on the run", but there was no indication that they were armed targets -- they could've simply been a group of civilians making a break together to get to a different part of the city for some reason. (If you couldn't move freely in your own city without risking attack, you might run from place to place too.)
Stan Goff, a retired US Army Master Sargeant, indicates the attack to be a clear war crime. You be the judge. (Nobody else will ever be...)
