You are not reading carefully SR. It's not a regulation because the USCG does not enforce it. The CG approves it, but it is ACRM's responsibility to enforce the safety conditions they attach to the MEP. Since two of the rules have been declared invalid, the RD would not be allowed to enforce...
What Barclay is saying is that ETNZ v LR can happen without a change to the MEP. Presumably he doesn't believe Murray has the time to revise the MEP before Saturday, and he's clearly got so much ego that he can't admit to being so soundly smacked down by the Jury. Not sure why that's so...