First, I'm a little behind on episodes, so jog your memory on this one.
The episode where Michael betrays the tribe (because that's what they are) in the hopes of regaining his son is completely understandable. Yes, it was horrible that he hurt his friends on purpose, but seeing it from Michael's point of view you have try and understand what he's feeling as a father. Doing anything to protect your children is what it's all about. I can't condone his actions, but I can understand them. If I was in that position, with my own son being held hostage, who knows what I would do? Hopefully not murder, but I couldn't gaurentee it. After all, being stranded on a not completely deserted island littered with hostiles is sure to bring out the instinctual savage in all of us.