The problem is we are often mixing non-statutory IP arguments with statist IP arguments, and it's important that people arguing for IP be clear on which they are arguing.
When they don't, there tends to be an assumption that the pro-IP person may harbor the idea there should be statutory IP law. This really undermines any useful discussion.
In the context of people who don't want a socialized system of IP, I think it invokes more passion than it should. In a stateless society certainly we will discover what people think about IP by their actions.
My strong suspicion is that where consensual arrangements to protect IP are possible, ie costs born only by the buyer and seller, there will in fact be systems to protect some IP where the cost to do so is less than the profit for doing so.