In addition to wikipedia, here's another source about no US state holding suicide to be a crime.
http://www.a1b2c3.com/suilodge/facenc1.htm
Even if it is a crime, there is no way that committing a crime means you lose all your rights and all your privacy. The accused and the convicted have rights, even if the convicted have some rights removed for a certain amount of time.
My personal opinion is it's for us to discuss if it pertains to the case -- the case that is about who killed Caylee, how, and when, and how the justice system deals with it. If there were charges against the A's for anything related to Caylee's murder, then we should obviously be discussing whatever is related to that (there's not yet). If GA's letter contained a confession or new information related to the case, then we should discuss it. If it just contained his thoughts and feelings about his family and his loss, I don't see how it sheds any light on the prosecution of Casey or justice for Caylee, which is my main goal for being involved in WS on this case.
It looks like this is just one where we'll have two separate views and each side will have to respect the other's right to hold that view. I won't be taking part in any discussion of the contents of the note, though, unless it's revealed that it is relevant to the case.