You've clearly never been deployed. You have more free time than you know what to do with.
Think about what you do when you get off shift at your job. Now remember that you have no family or friends that aren't also co-workers to hang out with. No alcohol, limited access to new movies and video games. You are also stuck within the confines of whatever base you're assigned to. If you're lucky there might be a one-screen movie theater or an internet café. You might even be able to get severely bandwidth-capped satellite internet in your tent/third-of-a-trailer-shared-with-a-roommate that you call your room.
Despite what you want to believe about Manning, lack of time was no excuse for indiscriminate leaking of sensitive information that honestly and truly put lives at risk.