AKA: I don't really know what this is, but it sounds dodgy, so I'm going to complain about it?
Jailbreaking is simply allowing users to use their iPhone in a way they see fit, separate from Apple's "walled garden." Some people find it useful to do more advanced things on their phone than Apple allows (third-party keyboards, for example,) some do it solely because they like "having the freedom" to do what they want. Some, yes, do it to load pirated apps.
I have waffled back and forth with jailbreaking. I liked some of the jailbreak-only apps in the past, but gradually apps with the same functionality became available on the official App Store (or the functionality became built-in to the OS.) Each OS version, more and more of the features I jailbroke for end up available "legitimately." With iOS 8, all of my remaining reasons will be gone. I will upgrade to iOS 8 on launch day, even if no jailbreak is available. And if no jailbreak ever becomes available, I won't worry.
I do consider the fact that jailbreaks come out to be a good thing, though. It both keeps Apple competitive, and helps find legitimate security holes and gets them fixed!