Probably what Rude is thinking, in regards to some of the fault being on him. Is that he didn't fully analyze what all was going on right before his shell went down, when it goes down and shortly after. He might have noticed each of those times, was during Krygas's use of life burst. Instead he let Krygas push all the blame on him. Also he probably isn't thinking he is at fault because Krygas rightfully got wrecked, but rather that bowing out as gracefully as he did, still resulted in the people that he cared about going through a ton of hardship. Though to be fair, I think he is being too hard on himself because he is the tank and Krygas is an arrogant jackass that didn't bother to understand his skills at all. Throw in the fact that he didn't know what two of his skills could do and it's fairly easy to conclude that maybe one of those skills was at fault.
Also not entirely sure why there is some hate directed at the two remaining party members. We know nothing how exactly how contracts are enforced in that world and it's kind of implied they are stuck with him because of a contract. Heck, they weren't even rude to him when he got booted by Krygas.