He's not belittling the tragedy in Norway, he's just framing it in the context of the brutality and slaughter that is dished out to animals on a daily basis. The incident in Norway is horrific and saddening; and he has acknowledged that- but also the treatment of animals is horrific on a daily basis. I'd guess that, for Moz, every day is like experiencing that feeling of horror, because the factory farming of animals, with all its abhorrent practises, continues each day.
No matter how offensive you believe his words to be, they are less offensive than having a bolt gun shot through your head, a fate that hundreds, if not thousands of animals will have suffered today in Britain alone.
To those who have lost loved ones in this tragedy, who have posted in this thread, you have my deepest sympathies. I can’t defend what Morrissey said, or at least the somewhat blunt way that it was expressed- those are his words, but I have no doubt that his words were said in sympathy, and were in no way meant to make light of the trauma your country has suffered. Morrissey is highlighting the brutality of two situations- human against human, human against animal.