Did a vigilante ROM leaker go too far to “preserve” a lost Atari ROM? (2019)

It's not morally wrong per se. Consider something like trespassing, where one could easily imagine a cooperative society allocating parcels of land for certain activities rather than certain people, but the way our system is set up trespass is widely viewed as inherently wrong. This is a similar kind of thing where it's wrong just because everyone believes it's wrong:

The problem is that you generally expect some amount of privacy and control with respect to your belongings. The fact that you've granted access for one thing (a repair) doesn't imply that you've additionally ceded other rights (copying a ROM) not reasonably necessary to the repair.

Similarly, you wouldn't expect your mechanic to keep your car an extra day to lend to their family, your plumber probably shouldn't be snooping through your closet, and your phone technician shouldn't read your emails. Those activities _might_ not cause harm, but they're activities you ostensibly control, so other people should acquire some sort of permission before doing them.

And yes, maybe physically stopping people is easier (locks on your closet, be home during repairs, camera and a gps lock in your car, password on your phone), but the physical capability of having your rights violated doesn't act as permission to violate them.