There’s no way this one guy could have obtained all of this info without help and support of others, not to mention incompetence of his superiors.
I don’t know, this guy is a computer geek.
There’s no doubt this wouldn’t have happened if superiors had acted on prior reports, it looks like PC raised it’s ugly head again. Their inaction allowed him access to get this info and he shouldn’t have had that access.
Unfortunately, this is pretty standard. He was a reasonably tech-smart kid. The security protocols are just restrictive enough to be annoying without really slowing anyone with ill intent down. That's just how the system is designed.
If you're a law abiding patriot, you're not stealing data because you don't want to. If you're not a law abiding patriot, well, then you don't steal data because you don't want to hang from the neck until dead. If you're too stupid to understand the situation, too traitorous to care, or too smart to get caught, then you plow along anyway and take your chances.
You don't hear about this sort of theft more often because most people that steal data aren't so stupid as to give it to someone who intends to LEAK it publicly. Manning may as well have stolen the data and put the links up on his Facebook page. That's more to do with his naivety than any unusual security lapse.