Outlaw motorcycle gangs recruit troops.
Actually, those gangs don't have to do a lot of recruiting. The vets tend to find them.
There's a reason for that.
You did that whole band of brothers thing in the Army or the Marines.
Your leaders shipped you off to Vietnam or Korea or Iraq or Afghanistan.
Guys who served miss that band of brothers when they're back in the USA and out of the service.
Those "gangs" pick up the slack.