Yea thats complete nonsense... the data is quite clear.. at best banning guns does nothing to help improve the violent, rape, and homicide rates... though at best it significantly reduces it (and the data leans towards the latter)
The number one death for children means nothing if you dont compare it to the number of children's lives saved by guns as well, or correct for kids killed in gun free zones.
Again this is like the anti-vaxxers argument "If you ban vaccines we will significantly reduce the deaths caused by vaccines"... while true its an intellectually dishonest argument.