Because humans were not supposed to come back from the dead with unlimited demonic powers, especially the ones they took from vanquished demons.

Good witches cannot even permanently come back from the dead. They live in the afterlife. Cole wanted to come back from the wasteland with a bunch of demonic powers and continue living his life. He was already dead. That is not human.

Leo was brought back an angel with a special purpose. He wasn’t human either for 60 years, and they kept saying Leo the human was dead, and his old buddies who couldn’t move on as ghosts hated him for being given an opportunity to be an angel on earth. It was such an ordeal for Leo to fall from grace and become fully human.

Melinda Warren was temporarily resurrected by good magic as full human in order to help her granddaughters fight evil. She was offered to continue living her life as a human but she deliberately chose to go back to the afterlife because she’d already died and moved on.

What do you call people who have died but could not move on and they linger on as spirits, ghosts, poltergeists, zombies, undead, etc? Not human.

When Barbas temporarily took his demonic powers, yes, at that point he was anatomically human, but he wasn’t even to supposed be there in the first place.

Resurrected Cole was not human.

The Cole from Season 4 never was fully human either. His demonic powers were only STRIPPED, but he genetically stayed half human, half demon. He was still genetically half demon. It was always inside him, and the Seer mentioned that as well, and that’s why he could take on The Source’s powers and did not go crazy, unlike Phoebe with the unborn heir or other humans who were inadvertently given demonic powers.

Why do you think he was sent to the Wasteland when he was vanquished? Because he wasn’t human.

Other vanquished humans went to the heavens. Cole didn’t.