Lena Dunham is human.
She makes a mistake once in a while — including offensive, knee-jerk response tweets — and she has every right to be as naked as she wants on TV. People might love or dislike it, but it's ultimately her choice if the network approves.
She can also wear whatever she wants, especially to awards shows. People might not like that, too, or even completely disagree with her choices, but that does NOT mean she should be fat shamed because of any decision she makes!