I am sorry about the man at the AA meeting. I know it must bring up painful emotions for you. Idiot is the right word...he's an absolute idiot. It's unfortunate, but it's a fact of life that we all run into this sort of thing occasionally.
Did anyone try to facilitate the talk away from that "madness"? I hope that future meetings are more productive, positive and healing.
It's understandable that this type of encounter made your depression worse. It just makes the challenge of working through your depression that much more difficult. Great BIG Hug for you. I can relate on so many levels. Hope tomorrow is better.