It is fine to have preconditions for a negotiation, such as "you need to formally respond to my offer first" or "these are the topics that will be under discussion" or "Dwayne Wade brings the pizza". It is something else entirely to require, as a condition for negotiation, that one party concede the very subject to be negotiated on in the first place.
If that's not clear, I am at a loss, I don't know how better to explain that. I could give an example, except it's one of those Don't Even Think About Posting This Outside of Current Events things.