Heh I know what you mean. People leaving is the #1 game killer in this game.
I confess that I did leave my last game, because my teammate was complaining at me (we were losing at short one person, but I got our team's one capture that round) and told me to leave. Ironically for him of course I was the host, so...
I was done playing for the day anyway. ; )
Despite that, I think yeah, people are already pretty uptight about leaving. You get a kill or two on somebody and they leave, or they simply join then leave without any explanation.
Now I'm not saying I expect a detailed apology everytime somebody quits, but it just seems like folks don't know what they want. It's not like anyone should have mastered this game already. I don't care how many times you beat the 6 hour SP campaign, that won't make you good at MP. And what game can realistically be mastered so you are unbeatable in 7 days?
One time (this was probably just a bug of not displaying the join message) it said a guy left who never joined. The "<name> joined" message never appeared! So a guy who wasn't even there in the first place, left...!
It may also be that people get bored fast. After playing some fun Assault for an hour, people start to disappear. Then I can sit in an empty game and wait, and wait, etc. I figure they must have gone to a DM server or something. So I host that and people return, repeat.
So many options I can't change on the fly. I have to instead, "disconnect" then relaunch the server with new settings. I can't even change my character's skin on the fly. It would be nice to be able to do that...
I lived with limitations like this in JK1, but that was 7 years ago...