Joel Hinrich Suicide - Something that has been bothering me

I was looking at Michelle Malkin's post on the Joel Hinrich suicide again and finally put my finger on something that has been bothering me. It was first reported that there was no suicide note found, but the FBI later stated one was located on his computer. Here is what bothers me in the description of the note:

"When discovered the laptop was on and in screen-saver mode. When the mouse was manipulated to activate the screen, a text document appeared. The document contained notes apparently written by Hinrichs to himself. At the point in the text document where the cursor was left, the phrase "Fuck all this. None of you is worth living with. You can all kiss my ass." was written."

This doesn't seem right to me. First off it implies that in the middle of doing something else Joel just decided, "Fuck it, I am going to go blow myself up at the football game. Now, where did I put my suicide vest?" I don't remember a whole lot from my psychology classes but that does not sound like a suicidal kid to me. It sounds more like someone writing a fuck you note to a roommate or a girlfriend. Second the laptop wasn't locked, so anyone could have typed that note. The initial reports were no note, but it sounds to me like the laptop wasn't secured immediately so how do we know that the note was written by Joel. [Actually they may be able to pull a timestamp off the autosave feature, but I am not counting on that giving any real hard data] I'm not saying foul play is afoot, just that the laptop evidence was questionable.