It sends the message that it's not a toy. #1 rule of gun safety is to always treat a gun as loaded...hard to play with a toy you shouldn't point, but must be pointed.
we grew up with all kinds of toy guns. most didn't shoot anything, at most a dart. we still pointed them at each other, played cops and robbers, cowboys and indians, war. I remember we even had pop guns. you cock the handle and it would shoot out a blast of air. we'd push it into the dirt and when you shot it you could pelt your buddy with a little wad of dirt if he was with in 5 feet. No one i know ever went on to shoot anyone. those toy guns did not make us killers.
I look at my kids. most of the guns they grew up sis shoot stuff. starting with nerf guns when they were young. then paintball guns as they got older an eventually airsoft guns that shoot plastic bb's. when they play their war games they are actually shooting at each other with a projectile. but none of them became murderers as a result. toy guns didn't make them killers.
my youngest son now has over 25 real guns. assault weapons with large capacity magazines. i'm talking some serious stuff. it hasn't made him a killer.
the problem is not the gun and never was. even a toy. but all of our attention is constantly focused on the object that is not even the problem.