Seems like some have an over inflated view of themselves. Let's take for example a customer in a bar or restaurant that arrives barefoot, smelly, dirty and drunk and he complains and want to be served more food/drinks claiming that the customer is always right and proceeds to also insult the owner... Well, if it was my shop, I'd rather lose that particular customer in order to preserve a better clientele so he would be shown the door. Lose a dollar, make a hundred instead of the opposite.
If this site was full of trolls and idiots, it would get likely get less visits and therefore less revenue. Up to the owner to decide what he deems a troll or idiot and whether an individual might deter other customers from visiting.