It sounds to me like the DM was just resolving the party conflict issue. I wouldnt blame him if all the other players were working together, and your character was causing severe conflict "out of game" by working against the team.
My current group has a player who is our cleric, and he is trying to charge us for healing and constantly make profit. It works against the team and is counter productive, so the frontline fighters charge him everytime they have to swing their weapons, the casters make him pay for spells. He stopped charging real quick. We didnt mind chipping in for potions/wands, but took offense at his "make a profit from the party" for using his free abilities. We even talked about leaving him in a town and just hiring a cleric or two for a cheaper cost then what he wanted.
That aside, even if the trap did so much damage to instant kill, should of at least been rolled. Always a chance to just barely survive. So again I think it was the DM removing a problem.
Last but not least, I played in a very fun game where I was the only "evil" character to begin with. I plotted to turn all the others evil, but worked closely with the DM. While the players knew I was evil, and the characters knew I was shaddy, I would not do anything illegal or evil in front of them. And even evil acts I kept toned down, knowing my party would turn me in or hunt me down if I wasnt careful. In the end I turned all but 1 character to the "dark side". The last character I plotted to kill (with the DM). Obviously just killing a character is easy, but to keep it fair I worked out an elaborate plan so the character had plenty of time to work it out. It started with paying bards and spreading rumors among thieves guilds of the players efforts to elimenate them. When assassins started coming after the character but not the party, he got suspicious. It was a lot of fun. In the end one of the other newly evil party members killed me off since I was full of myself and thought I was untouchable. So it can work, but must be kept balanced and fair, and done with the DM, not against the entire play group.