It's a matter of degree. A priest - certainly these days - is basically just expressing his good wishes for someone when he blesses them, and to be honest I don't think that you'd find a priest who'll curse someone. Excommunicate them, maybe.
The thing is, we understand that. Chris's view of blessings and curses is as the most childish concept of magic - he at least wants to believe that bolts of power thunder from his hands when he issues a curse-ye-ha-me-ha, and that sweet beams of balm issue forth when he performs a forgiveness blessing.
It's all about his infantile world-view versus that of a sensible adult. Chris wants blessings and curses to be like comic book superpowers, because he wants to have those. Anyone can say nice or nasty things to other people. But he's special.