It's easy to watch a show when you're sitting at home comfortable and seeing both sides of an argument and call someone closed minded. But even at the end of the series these people were still angry and in pain.
Not to mention the fact that Cally (Very realistically I felt) was suffering from major depression through season 4. Yeah she was whiney but that's how people get a lot of the time.
As for what the Chief saw in her; he himself said that she was the best of limited options. And to be fair the girl was very loving towards the chief for a long long time. And she was cute in a girlish sorta way. It happens.
Interestingly as well, going into the Psychology of some of the Galactica's crew, one thing I always noticed is that the Deck Gang was always some of the most vocal against the cylons. This I think can be pretty understandable. For starters they were put under a tremendous amount of pressure. Pilots had down time to rest up and training and patrol isn't exactly as full on as combat. Likewise for other officers and marines. The engineers and deck crew on the other hand was constantly full on. Why? Because there is always something to fix. There were no spare parts so anything that was full on busted had to be fabricated on top of regular maintenance. That's a constant high pressure job there. On top of that these are people who essentially fix up birds so they can send off pilots to die, and as they also doubled as damage control teams this also carried a lot of risk to themselves. All this kinda all adds onto the stress. In the end it's pretty understandable why Cally would be so loco.