How Hard is it to be Ready for a Game After Listing?

Seriously; what is the point of listing for a game, especially a Ranked game, and then spending the first 5 minutes tabbed out? I've had a few of these over the past several games, on one side or the other, and I just want to know, why do people think this is acceptable? Why queue if you can't immediately play? I get that sometimes things happen, like the client fucks up loading, or your PC goes down for some reason; but to be semi-afk, walking back to the turret every time you die to poke/a dive and just sitting there? And then, on top of that, then flaming people when you finally deign to give the game your full attention, because they haven't been able to carry your absolutely dead weight?

Do other players find these people in their games? Is it because I'm playing at odd times of day right now?

All this does to me is highlight exactly how toothless people have found the automatic player punishment systems that Riot have in place.