Just finished watching Unsolved Mysteries and wanted to add some thoughts. A: I wondered about Mom saying that she thought it was suspicious that nobody noticed when Josh left the room. I've never been to a school that small, so it didn't seem unusual to me that a dozen or so people would not make a special note of when someone that didn't seem to be in distress, leave an apartment. Would love other people's insight.
B: I had another theory about Josh posing as a woman in chat rooms. Could he have been exploring his identity, absolutely. That's an age where a lot of people do so and going to a religious school would be motive to keep it hidden. Back in 2002 the internet was basically the wild west and would have been a safe, anonymously way to explore.
That being said, it could have nothing to do with sexuality. A simple answer could have been that he had recently broken up with his long term girlfriend and was lonely. Men even now, and certainly back in 2002, don't always get the affirmation that they need. He may have thought that even the selfishly motivated and indiscriminate attention women often get was better than nothing. Just speculating of course.
I didn't find it that weird either. I've managed to slip out of gatherings quietly and unnoticed rather easily.