In my opinion, it is harmful to both SE & Christianity.
First of all, there are some very basic doctrines to Christianity. Forgiving the very immoral person should be a very basic one: I'm sure you could find sermons on this from across the spectrum, from Pope John Paul II to Luther to Augustine to C.S. Lewis to Rick Warren. I don't know that there's any fringe where there wouldn't be such a doctrine of forgiveness being available to all. Maybe the Nazis had such an extreme view on forgiveness--- it depended on your race?
Secondly, while we don't do counseling, the new believer/ seeker (perhaps somewhat presumptuously assumed by low rating and desperate question) could be given a basic scholarly answer. If they are a seeker, I don't think it's helpful to force them to pick a faction first up.
Thirdly, I've seen wide varieties of opinion across i) members of congregation, ii) members of an advocacy group pushing one kind of "reform" in a denomination, iii) congregations of a denomination, and of course iv) denominations. Saying, "I want the reliable answer of Denomination X" isn't often very reliably obtainable, if they want some sort of reassurance that they can go find specific people with a viewpoint. While I still hold that there are basic truths of Christianity, I don't think you can reliably find people who agree (who have been taught) the ones taught by the bible & church fathers.
Fourthly, it does imply that we are all idiots.
In contrast, it would be more helpful to simply answer questions as if Scripture, the writings of church fathers, the popes, the reformers, the evangelists (Spurgeon to Finney) and "famous authors" were all fair game, maybe even all in basic agreement. Let the different nuances come out in the different perspectives of the Answerers.