[ZeroGravitas]

The definition of the prisoners dilemma is that it is symmetrical, the only two parties involved are the prisoners and they want the exact same thing, and have the exact same motivations and payoffs and still can't agree on the best course of action.

Thats why it is a good toy example of this issue.

It is a confusing name for it, since in reality there are often mechanism to punish "snitches".

I prefer to think if it as two people wanting to make a trade without a framework to enforce any contract law. You both want to swap your items that are valued more by the other party, but since there's no mechanism to force you to be honest, you're both motivated to steal the other person's goods and not deliver yours. And so you both do that, and the trade doesn't happen, leaving you both poorer.