Personally I think it shows a lot of condescending elitism and general lack of class on Mr Peacock's part. Elvis Costello is great musician and a heck of a nice guy. Lee Konitz(whom i have met numerous times and am working with next week) is also a heck of a nice guy. You would think out of respect for Konitz and his birthday celebration - Mr. Peacock would have played the three tunes. This story disgusts me.
Obviously you only read Dwokin's one-sided story. If you do a little more research it turns out Konitz's birthday was a few weeks prior.
The rest of the important details we don't really know about.
Why don't you ask Konitz when you see him what really happened?