This thread (and Matt's previous self-responsibility thread) is kind of harsh. Many people are accusing Matt and some even say that he should pick a different hobby. While I am somewhat entertained while reading through the drama, some comments are just insulting.
Then again, the thread should probably not be in the Basic section but rather in the Whine and Cheese forum or the Near Misses forum, where people can more freely provide their criticism without worrying about scaring away new divers. As well, there are many excellent points here, if you sift through the muck.
I feel that the major problem (like Matt's previous problem) is communication.
1. Communication of the dive plan with your dive buddy (which you should always do with a new buddy or at a new site) - signals, specific plan, return pressure, direction, buddy distance, safety stop, emergency protocol (including lost buddy), and all the normal stuff that takes less than five minutes before even gearing up.
2. Social communication and perception - the major point.
a. the captain asks you a question in the middle of the ocean, you answer and don't give him attitude - this is for your safety. You only perceived that he was trying to be dominant, when he was probably just stressed that he thought you were in an emergency because you didn't signal anything. He apologized for his tone, but he shouldn't have to apologize for being worried about your safety.
b. people's avoidance of you on the boat - clearly you were emotional and stressed, and usually people will give you space to cool down. However, you perceived that they were avoiding you not out of politeness but because they didn't like you and thought you were a "pariah". They clearly were not, considering a couple of them asked if you were all right and one of them volunteered to buddy with you. You chose to be the social pariah by sulking alone (my perception).
c. your buddy knows what he did wrong, and he apologized - accept it; it's probably legitimate. Both of you made errors in the buddy separation. Don't read too much into it.
Look, you did some good and you did some bad. It's great that you're worried about your buddy and the separation. However, it was a new situation for you in the middle of the ocean, so you weren't sure how to signal or react. Your biases may have caused you to perceive others as hostile when they were not. You may need to learn to take things at face value and not over-interpret, especially since most divers I know (including me) are blunt and straightforward.
I'm glad everything is all right, and hopefully this is a learning lesson. I believe your diving attitude and habits may need to change or else a situation like this may happen again.