Soldiers, especially elite infantrymen and operators — who are considered among the best at their craft — find purpose, if not self-actualization in warfighting, and if we're to be blunt about it, in violence.
This is not a criticism, but an objective truth: just about everyone enjoys doing what they're good at — especially if they're being paid for it — including a certain variety of professional warfighters who've dedicated years, if not a decade or two of their lives to blowing shit up and killing people.
However, if you're a pipe hitter facing few(er), if any opportunities for making good use of your craft — perhaps as a result of disciplinary issues, conflicts with superiors, the mental tolls of war, the withdrawal of forces, struggles with substance abuse, peace and reconciliation, and/or the defaults of career progression — what do you do and where do you go?
Not to say SOF units in general or SOCOM units in particular are manned by "psychopathic killers," but due to a mix of both nature and nurture, they do draw and cultivate certain "types of personalities" that may be easily conflated with any number of tropes.
The overwhelming majority of these guys will find something relatively peaceful to keep busy with after their service, move on to law enforcement, or find themselves elsewhere in or adjacent to the government.
However, there will inevitably be a few who will decide to "go out of their way" or even "bend the rules" in the relentless pursuit for belonging, esteem, purpose and self-actualization.