You're missing the point.
People can make their own decisions when they're in a rational state of mind.
When people sign up for the army they shouldn't be scared, drunk, directly motivated by bereavement, etc.
Would you let a friend go swimming in the ocean (and I don't mean the nice calm, warm kind of ocean) after he'd had five beers, and brush it off as 'its his decision, he can do what he wants'.
Humans end up in situations where the sensible part of the brain which makes properly thought out decisions just gets turned off for whatever reason. Your house burning down in front of you is one of them.