If you were at the game, and are unhappy with how many opposing fans were there, then you should have talked your friends into going or bought them a ticket.
If you sat home and watched the game, and are unhappy with how many opposing fans were there, then you should have had your butt in a seat.
And if your excuse for either is that you didn't have the time, money, etc to go, or pay someone else's way to go, then why are you complaining?
I really don't see the big deal. It's a competitive sport. That means fans on both sides of the ball. I like the fact that Neyland is a place where an opposing fan would spend their money to go. And truthfully, I like playing against teams who have fans that show up.