Well, I can definitely see how they would feel it was better for them when we weren't there. We don't treat it like a library, we treat it as our lounge, study room, cafeteria, etc.
I think the way we use the room is not going to change, and that can be okay. But I do agree that we need to respect the room more, myself included. It's easy to leave a food container here or there, cause we think we're just going to pick it up later, cause we are always there, but that doesn't always happen.
For example, when people were playing EUCHRE! with my cards the other day, the cards suddenly got REALLY dirty, and I spent most of the following physics class trying to clean them obsessively. I've used those cards before, but never on a table that dirty, I suppose.
My point is, even if we use the room differently, we can still treat it like a library. I know that I, and many others, wouldn't treat the other floors of Thode in the same way.
Though at the same time, that is rude of them to talk of us like that.