Why? It might be because hacker George Hotz (right, from Wikipedia) in January published a method of taking control of the console's memory read-write and HV processor access functions, based on the feature.
Naturally some Playstation users other than Hotz are hopping mad, although how many even knew about the feature before this is unknown. A slim version of the Playstation 3 has never had the Linux feature.
Beyond upsetting some crazy kids and talented programmers I fail to see more than a symbolic action here. Game machine companies have always prided themselves on their proprietary natures, ever since the first Nintendo console.
I think the big news here may be that the moves by game companies toward turning their machines into real computers, which got their first market setback with the massive success of the Nintendo Wii, may finally have gone into full reverse.
Should the open source movement be upset over losing access to some game boxes? Or is this worth going to war over?