Yeah, what voltagex said. Same reason you shouldn't open-source a zero day exploit on any website without responsibly disclosing it to the company and giving them a reasonable amount of time to patch it.
They've basically made it open to the world, Apple has worked out closed sourced jailbreaks before with no help. Jailbreaks like Star (jailbreak.me) were just a PDF binary with absolutely no clue as to the contents or method of exploitation.
This is true, but making an exploit open source, as opposed to merely available, makes it significantly easier to weaponize for people who might not already be experts in exploiting iOS.
