So then re-write and submit an RFC...or go to IETF and join a WG - be open to discussion and speak up about what needs changed.

A MUST is a MUST, in my opinion - and too often there are serious issues in (web) communication because people ignore them as they see fit.

In either event - no one is saying that you should wait to change an RFC (or wording in an RFC) until it's fully deprecated and completely not in use - but a lot of people use RFC's for researching issues, especially in areas they are not 100% familiar with. Coming across a MUST and seeing that some software vendor or hardware vendor doesn't follow it is all too common. This delays certain projects by weeks, sometimes longer, and costs the involved companies lots of money. RFC's exist for a reason...because the approved standards are just expected to be followed when creating new things.