In a way, he has a point.
I'm a semi-professional classical muso, and if you're trying to accompany a soloist it's a lot easier if they don't throw in gratuitous rubati all the time. Two memories that come to mind are:

1. singing the St. Matthew Passion with a bass soloist who had about ten bars' intro to gauge accurately the tempo of the piece and then came in a good 30% slower, forcing the entire orchestra to grind to a halt in a kind of musical handbrake turn;

2. performing with a very famous French organist who was unfortunately also famous for making up his tempi as he went along, which if you're a choir trying to sing along to his accompaniment forces you to ignore 20 years of training and ignore the conductor completely in an attempt to stay in time.
( .Yeti., Thu 3 Mar 2011, 17:30, 1 reply)

Yeah, I agree that it works for a lot of music, and many soloists take the piss
But when it's actually written into the score... *shrugs*
(Sivvus trolley collision in the fruit aisle led to a jam, Thu 3 Mar 2011, 17:47, closed)