To me this just reads like "why bother selling whole free range chickens for roasting? It's pointless trying to shove them in your mouth as they're too big to fit and full of bones, unlike mechanically reclaimed battery chicken nuggets"
Olives with the stone in have a firmer texture and taste better - stoned olives tend to be stored in brine, which makes them salty and soggy.
Also - most stoned black olives are actually green olives dyed black - while there are different olive varieties they are all green when unripe and black when ripe, so the difference is when they're harvested. Black olives are ripe and therefore softer, which makes them less easy to remove the stones from without turning them to mush.