Well, there are two kinds of pirates. One who wants to be closed door knitted and don't want much (and probably don't offer much and avoid any risk) and then it comes 2nd type who really take piracy as a war. It doesn't matter to them whether they got caught for existed material or for leak, for most cases punishment is equal. And, the need to get things in advance at the detriment of quality is actually very tempting in piracy community. The one who release first gains more reputation in community and will attract more people. Take it as a race among groups; the one who'll win will consider as alpha and everyone wants to join that group, people will follow them and etc etc. I advise you to study how Scene works! All are actually fighting for best, fast and reliable. (everywhere) whether its' private trackers, public websites, forums etc. And, that leak was just a part of this regular exercise.
And, piracy is not actually bad for the artists; see how badly Indie artists die to get featured on TPB's homepage (when in promobay), piracy gives artists a recognition and actually it's artists that become arrogant and money-whore who starts complaining about it when they touch success. Otherwise you can't imagine an Islamic orthodox country like Indonesia has biggest fan following (of girls) of Justin Beiber.
P.S: I didn't write that article, I just shared it.