There is a huge body of information studying fire, ems, police, soldiers and the like. I didn't say it wasn't stressful. What does that have to do with anything? You are saying you don't wanna work with people because the job is stressful and you are assuming certain people can not hack it.
Who else won't you work with? Would you refuse to work with someone with PTSD? Those peer review studies you just mentioned have found that MOST FF/EMS/LEO's who show up at a mass trauma scene show signs and symptoms of PTSD. That doesn't mean they can't be a FF. That means they need to get whatever help they need, and keep moving forward.
It is appropriate to say... "Bill isn't pulling his own weight around here, and I don't wanna work with him if he doesn't get it together." It is not appropriate to say, "people with bipolar disorder don't belong in FF, or medicine, or police or any other role." Psych problems are an INDIVIDUAL thing, not a blanket and it is more wide spread than you know.