I think it's interesting what Guava Tree wrote regarding the difference between captains and first officers complaints being taken seriously.
Perhaps from the management's point of view, if a first officer complains about a captain's behaviour they are more likely to be commended for having the thoughtfulness to do so, the tenacity and bravery to do something about it and not be a wallflower. These are admiral qualities in someone with little experience and a good sign of future strength in character for command. It also gets you noticed by management for all the right reasons, especially if it is regarding safety, and can actually help your airline career, provided of course you don't make too many complaints then you become the problem!
However, if a captain complains about a first officer's behaviour they may be derided for not having the skills themselves to deal with the individual. Surely with all the captain's experience they could have figured a way to sort it out? The first officer's behaviour can be passed off as lack of experience.
(just a thought)