Insensitivity?

I'm not sure if this is insensitivity, but anyways, today, during a specific lesson (I'd prefer it remains anonymous), our class was very, VERY noisy, and the teacher had a very hard time teaching us.

She's actually a very nice and kind teacher, and allows us to talk in class (obviously at a certain volume), but i think today we have crossed the limit. I'm not trying to sound noble or anything, but I just think it's very unfair to her.

She tries so hard to teach us for our good, but we just keep on talking and not paying attention. If you were her, obviously you would be infuriated. We could not even greet her properly at the end of class, angering her even further. But even at her limit, she's still able to withstand the anger within (if there's any) and only asks us to "go away", and not "touch her things".

I mean, she doesn't scold us or anything, and only when we get too noisy she would raise her voice and tell us to lower our volumes; she's very nice, so I think we should know when enough is enough. Not that we should raise our volumes at teachers whom are not that nice, but still, I think that it was pretty unfair for us to not treat her with respect when she is trying to do the same to us.

It's our loss, not hers, and she's trying to help us. Shouldn't we try to not anger her?