Why do you even care whether if it's stolen or not?
You are presumably on MacRumors because you want Apple rumors and leaks (I cant see why else you want to be on this site). At least me (and virtually everyone else here) is here for the rumors and leaks.
The only way to obtain rumors and leaks is through stolen / supply chain / accidents / internal sources (snitches) / basically any method that is unofficial, improper etc., otherwise the news wouldn't be rumors. The very intention of rumors is to glean as much info as possible, regardless of how the info is obtained. That's the whole point and fun of the rumor mill.
I think there is a difference between rumors and extrapolations from the supply chain and blackmail/theft/breach of NDA. You can go a long way by following closely a company without going into the illegal territory. For example, hedge funds famously track private flights to track M&A activities or look at satellite images of factories parking lots.
Personally, I am here because I am a big fan of Apple products and want to discuss and debate 'possibilities' with other fans, in good faith. Heck, I even like the fact that some employees supposedly follow some of our discussions. I might be very, very, naive but it kind of feels like I am part of some kind of family of technology enthusiasts that connect with the vision that computers are not just a bunch of components soldered together, but can and should be crafted with care and attention, and be in service of the users.
I don't have the chance to live in California so I know I will never be part of that team or even that industry, but at least, here I have the impression that I am still part of it in some kind of very limited way. I am also learning things (about processors, screens,...) that I would not learn anywhere else.
At the end of the day, nothing is black and white.
At the bad end of the spectrum you have hackers like the ones in this news (who clearly have ill intent), in the grey area, you have the 'star' leakers like Jon Prosser (who I think is just a fan and probably too stupid to realize the damage he's actually doing). Personally, I am not OK with either but I can understand why some people like Jon.
At the opposite end of the spectrum, you have people like John Gruber who tend to stay far away from the leaks but do provide interesting takes on where Apple is going. This is the stuff I am most interested in and I am sure a lot of people here are as well.