Copenhagen Zoo's scientific director Bengt Holst has said the campaign to save a healthy, young giraffe had gone "much too far".
Mr Holst said all zoos had been considered to rehouse Marius, but there was no place - including at Yorkshire, where any space should be saved for a genetically more important giraffe.
He told the BBC it was responsible practice for zoos to manage animal populations to ensure they remained healthy.
The Danish response to the killing of a young giraffe has been muted - perhaps because Denmark is a farming country.
A UK zoo has offered to rehome a young giraffe facing death in Denmark due to EU in-breeding laws.