Speaking on the subject of the thread itself, I'm sure there are just as many reasons as there are hackers, most of whom probably have multiple reasons to not allow backups by themselves (Devolution as an example). They may simply be against it and only want to test their skill against the security on the console itself, others may be in a position to have to make that stance publicly. But when it all gets boiled down, in a scene like this they as the creators of their invention have say in how their final result is used.
Speaking on piracy itself, I have said before that I do pirate games. In about 75% of those cases, however, I either have bought one or more legitimate copies of that game over the years, almost always new or through an official download service. And quite often in cases where I hadn't owned a copy before, I ended up doing so down the road, because having the game was a great way for me to experience it and want a copy that was less hassle, having to make sure cracks were up-to-date and everything. Skyrim is a fine example of this. I wanted to try it, and ended up pirating a copy because I just couldn't afford a normal version at the time. But as soon as I could, I got the real deal. I wanted the proper game, knowing that I owned this experience, and knowing that it will work better as well.
Whether for trying games out or to experience games that aren't available, or even in the case of simply being able to play something, it is both helpful and harmful and is a part of the industry, both giving and taking. Piracy does have its place, even if it is an odd and precarious one.