In exactly the same way that the original "civilian casualty" figures were. Thats all that statistics are in a scenario like this - fuel to the fire for whichever side they suit.
And we know there are lies, damned lies, and statistics, so if they don't need your needs, you can always twist them into something you want.
So what do you do, you take the total number of dead, get an estimate from somebody as to how many were civilians, and how many were military. Given palestine has no clear military / civilian divide, that number was always going to be grey area. Its obvious that the death toll in gaza can be stretched either way - to show more or less civilian casualties depending upon whose side of the fence they sit on.
The interesting thing about that article was it refrained from driving a definitive line in the sand and giving exact figures, but instead pointed out that the number may not be accurate. Which of course we all know because we know how statistics work in conflicts like this, didn't we
Given that gaza has no conventional military, i think that militants who bare arms and attempt to attack isreal with rockets deserve no sympathy. Isreal is perfectly within its right to kill those have the intent to bare arms and attack its land. If these people don't want to die - the answer is simple. Don't pick up guns and rockets and stay at home.
On the other hand, I think Israel are bang out of order with its disproportionate response to that threat. Their trophy system means that most rockets do very little damage and the israeli casualty list is tiny. These rocket attacks do not give them cart blanche to launch airstrikes at whatever target this wish and to hell with any concerns about civilian casualities. Is the suspected militant outside or inside a hospital ? no matter, launch a missile anyway and it doesn't matter if we destroy a hospital, a school, or a family house in the process.
I'm neither pro isreal or pro palestinian in this. The palestinians could gain the ultimate moral high ground in all this and stop the attacks. Then Isreal would lose all justification for its strikes. Equally Israel could stop being so heavy handed with its retribution and instead improve their surveillance programs with an aim of pinpointing exactly who is doing it, and getting the palestinians to hand them over for firing rockets into isreal after they'd agree they would stop.
However neither of these things will happen. There is too much bad blood over too many years which means that neither of them will stop until the other one is wiped out. And Isreal is being funded by the US, so we know who'll win that battle.