He just said he would be for prohibiting all guns.
This is what always happens when I bring this strange logic up. Someone inevitably—INEVITABLY—says, "Well if it was up to me I'd make them ALL illegal." They say that in the heat of the moment, having been confronted with the nonsense of crying out for a ban of a type of gun that kills virtually no one in the country, statistically speaking, also forgetting in the heat of the moment that the other claim they are supposed to make is that "No one is coming for your guns, you paranoid conservatives...we just want "common sense" gun laws." So then someone usually starts backpedaling. Your strange post seems to be saying both in back to back lines.
The point is that you can't have both. You can't want to ban all guns but not want to ban all guns.
As for a logical argument for guns, what about the CDC estimation that as many as 3 million incidences occur each year of citizens using guns to defend themselves from violent crimes? That's not a good reason to have them?
That Time The CDC Researched Defensive Gun Uses