Last summer, my sister was sitting with her family at Shabbat dinner, when suddenly they heard screaming from their next-door neighbor's house. My brother-in-law ran next door to find a nineteen-year-old Palestinian stabbing the neighbours to death. My nephew, an off-duty soldier, shot the terrorist, which incapacitated him (but did not kill him).

Then he checked that the house was safe and attempted to help the wounded, until the security forces arrived.

In the aftermath, many people were criticizing my nephew for not killing the terrorist. It's painful to see pictures of the terrorist smiling proudly in court, secure in the knowledge that his family will receive more than a million dollars as a reward from the Palestinian authority, knowing that he will one day walk free, while three members of the Salomon family lie underground and the surviving family members had their lives shattered. Why didn't my nephew shoot to kill?

Such criticisms came from armchair soldiers - people with little knowledge of combat scenarios beyond what they've seen in James Bond. People with actual knowledge of such things are aware that such situations are chaotic, and that there's rarely such a thing as "shoot to kill." You shoot to stop what's happening as quickly as possible, and the largest target is the torso.

Once the attacker is neutralized, it's up to the courts to decide what to do with him. The IDF was extremely proud of my nephew's professional conduct and awarded him a medal. The goal of soldiers is not to kill terrorists; it's to follow the rules of engagement under very difficult conditions.

A different group of people are acting as armchair soldiers with regard to the situation on the border with Gaza. "Why did the IDF have to kill anyone? Why didn't they stop them some other way?" Such criticism invariably comes from people with no experience or knowledge of such situations. If they would bother doing proper research before publicly condemning Israel, they would discover the facts of the situation.

The IDF does not want to kill anyone - if you speak to people in the IDF, you would know that. And it's absolutely not in Israel's interests to do so. But sometimes, situations arise in which there is simply no choice, if you want to prevent much worse bloodshed from happening.

There were not only protestors present - there were also numerous Hamas terrorists armed with butcher knives, guns and firebombs, whose explicitly declared goal (as can be seen in video footage) was to break into Israel and kill people. The terrorists were mixed together with the protestors in several huge mobs. And there is simply no way to stop them at a distance without using guns.

The IDF used tear gas, but its effectiveness is dependent on wind conditions, and the canisters can be quickly buried or thrown away. Rubber bullets only work at short range. And you can't wait for it to be a short-range confrontation - with a mob of thousands, many of whom are armed, it would turn into a sheer bloodbath, on both sides.

"But Israel is so technologically advanced, there must be non-lethal ways of stopping them!" No, there aren't. No army in the world has yet discovered a way of stopping enemy combatants without using bullets.

Maybe one day there will be such technology, but it does not yet exist. It's the height of irresponsibility to condemn Israel's actions based on a completely fictitious, baseless claim of the existence of "alternative technologies."

"But it ends up being so disproportionate - sixty Gazans dead, and no Israelis dead!" This is perhaps the most bizarre criticism of all. Should Israel wait until the Gazans had broken through the fence and killed some Jews before stopping them from killing any more? You don't measure the morality of a confrontation with terrorists or of a war by comparing the number of dead on each side.

Unless you're one of the many outright antisemites who believe that Israel has no right to prevent its civilians from being butchered by terrorists, then please, show some responsibility. Don't criticize the IDF's method of preventing a larger bloodbath if you don't have any expertise in this area. Learn what the IDF says about these situations.

Contact soldiers (as I did) and listen to what they have to say. If you don't trust the IDF, then listen to what Colonel Richard Kemp, former commander of British Forces in Afghanistan, has to say about the absolutely necessity and propriety of what the IDF did.

Don't be an armchair soldier. It's morally irresponsible. And it's plain stupid.

Rabbi Dr Natan Slifkin is Director of the Biblical Museum of Natural History in Beit Shemesh, Israel