A guru is your idea of perfection. It's your role model. You look up to each and every action of this person. You love, respect, and admire him so much that secretly you wish at least to become part like him.
To be like your guru, you can't pass judgement on him. Can you judge your idea of perfection? You can't. The moment you judge, you put yourself in a superior position to your guru intellectually, and now say you have the power to judge. You are judging your role model. That basically destroys the concept of perfection in your role model.
When you are lucky and you happen to find a guru who is your idea of perfection, don't judge him. To get the benefits of his superior attributes in your mind, you have to unconditionally surrender. Once you do that, you will stop judging and start seeing the wisdom in his actions. Slowly, those same actions will become part of you. That's how a disciple becomes a guru.