According to the Devil at the end of the film, she and God are both fairly affable chessmasters that just tempt people in either direction of the morality spectrum, but humanity is still responsible for most of their own happiness and misery. Yeah, except for the part when she replaces a bunch of hospital patients' medicine with various candies, likely ruining the lives of arbitrary loved ones everywhere.
Thus the "most" in the Devil's phrasing. Remember when it's only pure luck in timing that stops Elliot from dying when he becomes Abraham Lincoln? She certainly has no problem with endangering people's lives.
Sounds reasonable to me. The Devil may do some evil things, but isn't it God that's responsible for children being molested and houses burning up with people inside?
Wait, I think that was a communication mishap on the part of the original poster. I think the original poster meant that sometimes when horrible disasters happen, God's followers claim that God works in mysterious ways. So, sometimes people could get the impression that God is evil from the way his followers portray him. I think that was the original poster's actual argument. The original poster could have phrased it better, admittedly.
Or it could mean an all-loving, all-powerful God could prevent those things, but doesn't. This is known as the "Problem of "Evil."
Then there's the fact that she's, you know, evil. What's to say she wan't lying?
I kind of assumed everything that he saw during his encounter with her was suspect and might just be images she's putting in his mind. It's not like he REALLY turned into Gene Simmons or whatever.
This is quite possible, as it would go towards being All Part of the Show. She's got to convince Elliot that she's an utter Card-Carrying Villain, so she fakes a couple of incidences of doing stuff For the Evulz. Either that or the whole Satan Is Good thing was an eleventh hour addition to the script when they couldn't figure out a satisfactory ending otherwise.
Why didn't Elliot ever call the Devil out on the first wish being counted even though he made it and then signed a contract guaranteeing him seven wishes? I'm sure some sort of clause in the contract would have been brought up to Hand Wave it away, but it's strange that he didn't even try.
He did call her out. "Well, that doesn't seem fair." "Fair?! Just who do you think you're talking to?"
Think of it this way. If you buy a car from me and I hand you the keys before you sign the paperwork that doesn't mean I still owe you another car.
Also, the Devil might have specifically went after Elliot because he was so easy to befuddle and intimidate and not ask those kind of questions (at least, not ask while still recovering from the shock of meeting the friggin' Devil).