Using the term "Intellectual Property" would be the same as using the term "patents on computer implemented inventions" instead of "software patents". You're using a term created by lobbyists with a certain agenda and that agenda is deeply embedded in the term. If we keep using the term, I think we have already lost half the battle. The problem is that "IP" is very different from real property. We might see that, most other people don't, and that's why we have to make it clear that it isn't like real property.
You can actually try to define "IP" to some (for politicians too difficult to understand) 3 lines long definition, but that doesn't change anything in the minds of decision-makers. They will about it as property and act that way.
The best example of the effect of the use of the term "Intellectual Property" is when you compare the dead EU constitution with the US constitution (when the term "Intellectual Property" did not exist). The EU constitution says:
"Intellectual property shall be protected"
Of course, that's logical, if you call it property. Now the US constitution:
"The Congress shall have power to promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries."
I think the difference is quite clear.
The question whether to use the term "Intellectual Property" is not about whether the term is correct or you can find some academic definition for it. It's the question about what your goals are. Do you want decision-makers to think about copyright/patents/etc as property? By using the term "Intellectual Property" they will. And things like IPRED are just a logical continuation of thinking about knowledge and culture as "property".
If you look at the viewpoints we're trying to convince others of, using the term "Intellectual Property" is counter-productive.