Alot of people really need a reality check. Do you really think Sony didn't have a team of lawyers looking over what they were about to do? The company knows full well before they do someone what the legal implications are. Which means that yes, Sony knows that they will have no legal problems removing Linux.
It goes like this. PSN is a service, provided to you by Sony, and you can use it at your discretion. A requirement for using this service is having the latests firmware. Sony believes Linux is a security risk and removed it. If there is a game that requires the PSN, then they are legally justified.
Yes, this means some of you who don't update won't be able to play the newest games, because they require the latest firmware, regardless of PSN access. This is a consequence that later firmwares are going to add new features (cross game chat).
Bottom line is, if you used ps3 for linux, sorry, you're out of luck. You aren't going to be able to take Sony to court. You can't sue. Legally, you're rights have not been violated. Personally, and in your opinion, you probably feel so. Sell the PS3 and get something else.