What does " red -rope" mean ?
A source with a foot in the Moss camp told me: ‘Kate is prone to a
spot of red-rope rage, which is what happens when someone who has been
famous and sucked up to for their whole life encounters ordinary
people who say things like: “She doesn’t look like she does in her
magazine pictures,” and, “Isn’t she drunk!” Or they bother her for an
autograph or a selfie.
Best Answer
It is common at publicity events such as film premiers for the stars to walk along a red carpet to the event's entrance.
Lesser mortals, both press and public, are kept behind a barrier and off the carpet. This barrier is usually made of a red rope, to match the carpet.
Those behind the red rope will take photographs and ask for autographs. They will also gossip amongst themselves about the celbrities walking past. The quotation you give indicates that some celebrities take exception to some of the comments that they hear. Thus 'red rope rage' is a euphemism for the expression of discontent by a celebrity at comments from people at such a publicity event.