Can you imagine publicly badmouthing a former client and what it would do for your reputation? It wouldn't be good for the way potential clients perceive you in the future. Imagine the dynamic between client and service provider that would allow for this kind of arrogance. Maybe the move wasn't made in error and instead intentionally sends a message to the others: hey, petty makers of things, you need us more than we need you. And be careful what you say 'no' to or we'll punish you for it.