For one thing... visibility... do you honestly think bungie has time to go over each and every single time a group has gone after Crota? In Crucible people get reported and bungie investigates reports, such things do not happen when someone goes into it with a group of people of their choosing to mess with his mechanics. In order to discern who glitched Crota they would have to inspect every single Crota kill event to see if it was glitched, and furthermore actually inspect what happened in the Battle to determine the difference between someone simply disconnecting because of legitimate reasons, or deliberately did it to glitch Crota, because they obviously can't just ban everyone who has ever lagged out during the Crota fight. I am by no means supporting using glitching to kill Crota, but at the same time I realize the reality of the situation is, even if they started handing out Bans for it, likely they would only manage to maybe get 1% of the people doing it, in which case haphazard enforcement of policy would undermine the nature of the service they are providing and make them seem foolish lashing out against random people. So Bungie will do as they have always done, turn a blind eye until they figure out a way to patch it out of existence and move on with life, much like they did with Atheon and the Templar