Dude, it doesn't have to be detailed. We are raised from the dead by our Ghost at the beginning of the game, and then raised from the dead throughout it. The Traveler's Light, which both Ghosts and Guardians use, is referred to as an almost supernatural force. That's all the detail and explanation we need. And again, no major company is going to issue an official statement because some random dude posted BS on Reddit. If the guy had actually offered proof, that'd be one thing. Instead, he just claimed to be an 'Ex-Employee'.