The angels on my world can't touch the Spirit of Vengeance power directly. It's some kind of safeguard. But it was the only power Zadkiel could use to blow up heaven's walls so he could stampede in with his Black Host. I was already a junkie. The exorcism was a mistake. A week afterward I was so bad I tried to light myself on fire in Times Square, got my picture in the Bugle for the whole damn city to see. Probably the country or even the world, I think it and the article was on their website.
Zadkiel just took advantage of the opportunity to manipulate me into giving in too much to the Spirit. We can overdose. Give in too much and the Spirits grafted to our souls cannibalize the rest of our soul and leave us with nothing but aimless vengeance. We become total monsters worse than the fucking Punisher. He knew that stringing me out, finally giving me the full dose, and then killing Mary would make me do just that, and he knew that I'd dedicate myself to him if he offered to save me from becoming that.
I was too blinded by addiction to ask the smart questions or listen when Mary told me I was in over my head. He used me and once I had collected all of the power by killing every other Ghost Rider - my brother included - he pointed me like a gun and used me to blow down heaven's walls.