The IDF investigated and determined that lethal force was not necessary, and that the soldiers' stories about what happened - that Kahla tried to grab one of their guns, or tried to stab them - were not accurate.
So far this year, there have been 18 Palestinians killed by Israeli forces in the West Bank. In nearly all of the cases, the person killed was actively involved in hostilities when killed and/or was a member of a terror group. (Given that there are millions of Palestinians and, at most, only several thousand members of terror groups in the West Bank, the chances that terror group members were not involved in hostilities and were coincidentally killed is quite small.)
Here is what most of those killed looked like:
Adin Haykin has been keeping track of the deaths and the circumstances/affiliations.
Notice that two of those pictured here are children (#1 and #8.) There have been four child terrorists killed this year, three of them PFLP and one Fatah Al Aqsa Brigades. That story, that terror groups are actively recruiting and training children, is simply not reported anywhere.
The case of Ahmed Kahla is the exception that proves the rule - the IDF tries as much as possible to only kill those who are directly attacking at the time, which is the vast majority of those killed. Moreover, the deaths are investigated, the investigations are done by high level authorities and the IDF will admit when their soldiers violate policies and kill without enough justification. (The last time the IDF admitted to have made a mistake was in December.)
Soldiers are under intense pressure, knowing that they are targets 24/7. They often have to make split second decisions as to whether they are being attacked and from where. And, crucially, they know that if they make a wrong decision, not only could they be responsible for the death of an innocent person, but they may face investigations.
The media typically does not report on most of these cases of actual gunmen attacking soldiers; far more often they will just report a tally of those killed and imply that most of them were uninvolved civilians.
But as we have seen, well over 90% of those killed are very involved and active in hostilities when killed. And in Arabic, their "heroism" is celebrated.
