What do militaries do on the peacetime?
And then add to that that in EVE "peace" means "fighting without headlines". There's still a whole lot of things left to be done. Policing, corporate security, intelligence, counterintelligence, sabotage, counterterrorism, monitoring the pirate groups, monitoring your own workers, monitoring revolutionaries, exfiltration (hiring your competitor's employee), objective raids.
And for the ex-corp sec guys, the list just grows, as they are deniable resources ("no, it wasn't Peace and Order Unit that did abduct that Lai Dai researcher, honest"). And even more if they're willing to turn a blind eye on law, or work in the lawless regions.
