Used to play rugby as well actually. In football, if it goes out for a throw in then invariably there is some doubt about who touched it last. I made the point that I would always claim it, even if I knew it was not my throw in.
In rugby, there is never really any doubt about who carried the ball out or kicked it out so there is no room for rugby players to contest the decision.
Regarding your last point, I am not saying I am offering "real insight". Just saying that (guessing by your reaction) that you have no experience of playing football competitively and thus can't really offer a proper view on my opinion that footballers should be claiming everything.