Not true. That may be what it is intended for, but there is nothing to regulate what people think or vote. 99% of votes won't have anything to do with the decency of the person, but just how much of a friend to the voter they are.
But the more 'decent' a member is, the more friends they are likely to have, which would result in a higher rating. If a member is nothing but a douchebag, and isn't popular, their rating will be lower.