Just as the ending of the linked article pointed us to think about who we can and should trust. In matters concerning my physical and spiritual health, I would definitely be adhering to the advice of one who is stable, consistent and have good motivation in their thoughts and deeds. In spiritual matters, the guru would be the person to lay one's trust on all the way, for the guru would be the one to bring us to our enlightenment. As mentioned by SabS, our perceptions that stems from our ignorance and ego would lead us to making wrong conclusions. It is best to follow the instructions of one's kind teacher.