Zoo staff received death threats after the killing on Sunday of the 18-month-old animal, named Marius, which shocked animal lovers around the world.
Thousands signed an online petition to save him, with a billionaire even offering to buy him and keep him in her Beverly Hills garden.
But in Denmark, a nation with many farms, an overwhelming majority of social media users felt the global outcry was a sign of hypocrisy and political correctness.
A leading expert on the ethics of the treatment of animals decried the "Disneyfication" of zoo creatures.
A journalist for the Politiken newspaper, Kristian Madsen, wrote on Twitter: "The whole world has gone crazy. What do they imagine the lions eat on days without a treat such as Marius? Brussel sprouts?"
Dorte Dejbjerg Arens, a project coordinator, said: "I'm still livid over Marius. How can people get so hysterical over a giraffe while cancer, the war in Syria and the (anti-immigrant) Danish People's Party still exist."
The giraffe was put down with a bolt gun and then chopped up and fed to lions in the zoo, as visitors including children looked on.
The zoo said on its website it had no choice other than to prevent the animal attaining adulthood since under European Association of Zoos and Aquaria rules, inbreeding between giraffes is to be avoided.
One expert said the relatively muted public reaction in Denmark could partly be explained by cultural factors.
"Denmark was urbanised relatively late, which is why the general opinion here is that it's okay to keep and kill animals as long as you treat them well," said Peter Sandoee, a professor of bioethics at the University of Copenhagen.
"Animal rights activists in Denmark aren't nearly as strong as they are in Britain or the US."
Arguing that "one of the most fundamental aspects of animals' conditions in the wild is that only a fraction of them survive," Sandoee lashed out at what he called the "Disneyfication" of zoos.
"You take this very romantic image of animals as people with fur or feathers. Animals are viewed as a type of citizen, with the implication that they should be treated on par with fellow human beings."
A zoo's primary job should be to preserve different species and contribute to learning about how animals live in the wild, he said.
In the past, the Copenhagen zoo had allowed tigers and lions to reproduce, killing the "surplus offspring" rather than castrating the animals or giving them contraceptives, he added.
"I think Copenhagen Zoo takes a progressive stance here because in doing so they (mimic) the animals' natural life," he said.
Copenhagen Zoo said two other zoos had offered to take the giraffe, but that one was already part of the same breeding programme, while the other didn't have the same code of ethics.
"They would not, for example, sign a statement saying they wouldn't sell their animals to a circus, and we can't just close our eyes and send our animals anywhere," scientific director Bengt Holst told public broadcaster DR.
The Natural History Museum in Aarhus has invited children to visit to watch autopsies on animals this week, which is when many students have their winter break.
"An experience that triggers ... the curiosity and most senses!" the museum said in a statement.
Among the animals set to be dissected in public are a raccoon, a badger and a blackbuck, a type of antelope.
Organisers told Politiken that the event normally attracts between 7,000 and 8,000 people.