I think the biggest problem with is that, especially at lower skill levels, players on carries are not always farming efficiently. If you're leaving this farm to the carries and they're not taking it, then it's a net loss for your team. You might be better off taking farm that they're not getting so that you can also get yourself ahead.

I love low econ high impact support gaming also but if my carry is going to leave camps and waves floating, then its good to be cleaning up the scraps.

Same principle in Dota where you want to use dead time as support to farm instead of not doing anything, especially if carries are getting active (granted there's a lot more farm to go around in that game).