Logically speaking, it seems pretty silly to boo this team. Struggles aside, they're in first place in the East and have a track record that should earn them the benefit of the doubt.
However, it was cold, and people are drinking, and they spent a lot of money (like, a LOT), and for many of them it's probably they only game they get to go to all year. So I can't blame anyone for letting their emotions sail.