that controversy was just one guy making a stupid comment about how "you can't shoot properly with one hand", probably trying to pass himself as some gun expert. Having done competitive shooting in my youth, not only you can shoot like that (it's 22LR, the recoil is low), but as it was mentioned, you HAVE to. Technically, it's not so much as "put your hand in a pocket", but "hold the gun with one hand". Placing your hand in a pocket or belt is just to fix it in position in a way that won't tire you out and increase stability, so it's very common to do so.