I see you can't even manage to convince yourself of your own argument.
The Orcs didn't trust the Draenei at all by the time the demons showed up, that is the only thing you're right about. However, in addition to the other things you've failed at, you've even managed to get the definition of warning wrong, let me help you with that
a statement or event that indicates a possible or impending danger, problem, or other unpleasant situation
A warning about the Eredar and the Burning Legion wouldn't have done much good by the time KJ showed up, because at that point it wouldn't be a warning, it would just be a statement.