If Christianity is just another "made up" story...

Psychological for the most part. The possessed fools believe in that stuff so a little holy water and they cure themselves.

However, I do give the slight possibility that there may be powerful spirits out there.

Also, remember that Christianity is not the only religion which exorcises demons from fools. Muslims, Hindus, Buddhists, pagans all have such rituals.

THAT's your gotcha question? Lol!

Because those symbolic items are invoking God's intervention.

There are people of various religions who use other items to invoke God intervention which work. God is the real power, not the items used to ask for his help.

I'll add that I don't believe there is a "right" religion or God favors any if he exists.

If someone believes themselves to be demonically possessed due to mental illness (e.g Anneliese Michel) an exorcism can help rewire the brain into believing that the "demons" are being cast out. It's like a placebo effect.

That wasn't a very hard question to answer lol.

Also, if Batman isn't real why isn't the Joker causing havoc in the real world?

Why do pseudo-scientists like psychologists have so much power over people (granted, they have drugs to help them manipulate the minds of their victims)?

Two songs come to mind:

"Whatever gets you through the night"

and

"Confessing all the secret things
In the warm velvet box
To the priest, he's the doctor
He can handle the shocks…"

I'm not a practicing religious person. I do think Christianity gets a bad rap considering it's just another religion, so I try not to pile on and I will defend Christians when I feel they're being unfairly attacked. However, at the end of the day, religion, psychology, astrology, these are all belief systems designed to cushion the terror of mortality.