Not all [drunk driving/gun owners/tobacco smoking/drug abuse/crap diet/soldiers in war] die or cause death. So? Should we turn a blind eye to those even though there is a clear trend in harm to others?
This is a bad argument. Drunk driving is not a belief system.
If we are to ramp this up a little, things like demon possession were ways for a culture to talk about things they did not understand, like mental illness. in a pre-scientific age. They know something is off, it's just that instead of understanding it with a scientific view of chemical imbalances, pyschological traumaus, and the like, they called the same thing demonic, it is caused by "spirits" and the like.
Prescientific cultures functioned. Even if they were "wrong" about the cause, or rather their cause of "spirits" was replaced with a cause of "chemicals", they had a functional system that worked for them. And in all honestly, a lot of the symbolisms involved in "healing" people, are not that far off from the cures we employ today. You get far to hung up on a literal understanding of these things.
My point being, a functional system, does not compare with drunk driving. Nor does it lead to the things that this mentally ill individual did. If that was so, this would not be shocking news at all, to anyone. But it is. Which means, it is an aberration, not the norm.
Should we not be concerned about televangelist exploiting people?
And keep in mind, dead children from parents who believe in superstitious nonsense is not an isolated or rare occurance.
Of course if someone is breaking the law, yes we should be concerned. But your notion that superstitious beliefs are the cause of bad behaviors, is not supportable. If it were, it would not be news. It would be the norm.
BTW, there are lot of people who are harmed by the views of modernity, such as shoving pills into you rather than fixing the mental illness through psychological therapy. Yet, exorcism is considered primitive? We don't have the "truth" as much as we might like to think we do.