I think this depends on what you mean by second favorite team. I lived in Wisconsin for several years and attended several Packer games at Lambeau. I consider the Packers my second team and would root for them if they were playing somebody besides the Bills unless it were going to hurt playoff ranking or something.
That said, I don’t root for them on anywhere near the same level as the Bills. And if they play us, especially in a Super Bowl, there would not be one ounce of me that wanted them to win.
So second team, yes. But second team on the same level as your number one, “die hard” team, not a chance.
I watched a game at the Cheerful Bullpen a couple of years ago. Good time and good crowd. Enjoyed it! 👍