I agree with most of that. I don't think they should ever say that on the phone, but there is no way Apple is not aware CS agents are saying this. As Adam said, he found this has happened before enough that it would be on a Google search. My problem is, if you are willing to let CS say that on the phone, then you better own that s*** on Twitter, and do it there too. I don't want want to support a company that will say one thing to me for the world to see, but tell something completely different on the phone. I find that very discomforting.
A good joke should not need explaining. It's even funnier in light of the fact that it went so far over your head, it probably brushed the moon
In case you don't know, those in customer services are taught to cease all communication once the customer "threatens" the company. So, yes, "Are you threatening [insert name of company]?" is a common question asked by real CS reps when the customer appears to making threats, but the point is the OP made no such threat even in his phone conversation.
This is also why it's never a good idea to threaten a company when things don't go your way, because it'll defeat the purpose of eventually getting what you want.