Me too. Usually I'm pretty allergic to irritating MC's, but barring Cam's impulsiveness stealing the ship (in the very beginning) there's nothing bad about his behavior. I actually think he's quite likeable.
Out of curiosity, what are the things that rub you the wrong way about him? How does he develop (to be worse) in your mind?
I think that he is an overconfident, entitled little child. And contrary to what others may say above I don't think he actually matures in any tangible way as the plot progresses. He starts as a douchebag and that continues. And he is a poor captain. Even though some of the crew have cases of misplaced hero worship, they are the ones who actually keep him from really fucking up.
He comes from rich nobility (minor or not, doesn't matter) and the cushion that gave him allowed him to rebel and corrupt others. He has not actually demonstrated genuine care for anyone apart from wanting to bed them all. He dragged the Szuzume kids down with him and there are subtle lines of dialogue throughout where he attacks their mother...fueling their decision. They are actually quite weak mentally and are easy to control. When something that he cannot overlook (Eva's abduction) comes along, it takes precedence over everyone else's lives, which demonstrates selfishness. He is actually quite unapologetic to Thim. His asking of Thim to be a doctor is highly contrived and again only shows his shallowness at achieving his goal...hell with everyone else.
I think that Thim's character shows more maturity and decency than the MC.