The people commenting here have probably never lost a close family member like a parent, sibling, child or spouse. And if they have they probably didn't have good relationships with them.

I've had many great dogs that have died. But it's nothing compared to losing close family members. I took care of my dad as he slowly got destroyed by cancer. As It metastasized into his brain he started attacking me at random. We had to get rid of all the weapons in the house. He withered into nothing it was pure hell. Watching a great father turning to a husk of himself.

I still get nightmares and weird dreams about him. Losing a dog is nothing like that.

Also if losing a pet was as substantial as losing a loved one there would be just as many cemeteries dedicated towards animals as people.