The simple fact is that most "hackers" aren't hacking the console to run roms or backups, it's quite literally people attempting to find out the upper limits of a device. More often than not, the people who are finding exploits are doing so to find something new. Against piracy or not, when you release something that can lead to piracy you're basically allowing people to steal others work, which they themselves would be quite upset for if it were to happen to them.
It's not self importance or selfishness from a developers stand point, it's basically courtesy towards other developers, though this is only my opinion and many of the developers would disagree with me, everyone has their own views on their reason for their standpoint. One developer may agree with piracy since they believe in open source whereas another may dislike piracy as it's seen as theft, stealing others work, and most developers understand how many hours go into creating games that are released, the sad fact is, when any console is hacked to the point where kernel access is achieved, where it gives developers the freedom of the device in question, it does mean that someone else may simply want to use it just to play games they can't be bothered or can't afford to buy whereas the original reason for wanting that unimpeded access is simply to create something new for that device, namely a homebrew app, something their own and not others work.
