There are a few reasons, IMO - and many of them differ depending on what your motive is and what your feelings are about this nightmare of an org.
Primarily, for most that have a deep hatred for this cult, it's just good to see that the organization has chinks in their armor and we hope that one day, they self destruct from the inside out. I'm in the camp that loves to see governments crack down on them, and I especially love to see them exposed over the hiding of pedophiles and harboring of monsters (for example, the ARC stuff). They suck, I can't stand them, and I often check this site for no other reason than to daydream about when those bastards finally fall apart.
At the same time, we do live in a society that is obsessed with anonymity online. The internet is full of "tough guys" behind a keyboard. People like the Snowden's of the world, and the crowd that loves wiki-leaks are prone to getting their rocks off on anonymously revealing things that they are privy to. It makes them feel like they are smart, getting a "one up" on the WTBTS. That's definitely part of it. If you are in the borg, but having serious doubts, you use information to curry favor and support from those out of the borg. There's a lot of ego involved, IMO.
Second, I think there are people that are out and free - but they still want to feel like they are still in know (the informed, inner circle) of the borg. These people love that they still have access to all of the tasty gossip and information that they did when they were in. It's similar to what people that Trump have fired have had to say about his presidency, after they are out...some measure of sour grapes.
I am sure that their auditing department (IT Budget) is spending a ton of money on DLP technology (data loss prevention) and trying hard to audit everything that is accessed and copied elsewhere. I bet they run Splunk, Checkpoint DLP agents, and have endpoint encryption on their servers, desktops, and laptops...up the wazoo - and go through detailed audit logs on their internal infrastructure to see who accessed what, and when.