You can't question Q! His wisdom is infinite!
But really, the point was that since he didn't fight to protect his fellow man, it was a pivotal time which turned him in to a big softy who never took chances, stick up for himself and others, or made a name for himself which is why he became Science officer #15425-b who was stuck doing mundane, boring shit in a lab.
You know, existential crisis or something of the sort.