Don’t know much about the LEGO cannons specifically, but in the USA there was definitely a broad, somewhat hasty transition to non-shooting versions of many shooting toys after a toy spaceship’s missile killed a kid in 1978. Missile-firing toys have been creeping back into the market in recent years, but there were almost none for a long time.
#Murica! Where we can still have guns for hunting game or schoolchildren, but our kids’ toys can’t have plastic projectiles because #youllshootyoureyeout!