Yes if he had a gun the death toll could have been higher but if others had been armed he might have chosen a softer target where others are not armed or he might have been dealt with after the first shot.

The people did indeed step in and prevent the guy guy from taking more lives but it doesn't always turn out like this. Attackers usually choose places where nobody would be armed and he thinks he can do his deed without fear of being stopped.

About the comment about motor vehicles, I was talking bout England trying to ban knives now and how ridiculous it is. If the attacker had used a car or a truck to kill people would they chose to ban them, no, it would be too difficult but a knife they can ban because nobody will object much and it will look like the government is trying to protect them. Again blaming the weapon instead of the person using it. Governments can't take on the big job of dealing with violence itself.