That's what they need to fix, and they do have grassy fields on campus that could be used I think. What if they had several tailgating locations if no one field is big enough?
But it's not that tailgating can't be fun, it's just that you've got to do it right, and you're absolutely right that it needs to be where grass is available. It needs to be comfortable for all ages so that it isn't about wasting your day waiting for the game, but rather about a fun family event that is fun by itself, regardless of the game.
In Georgia they'd get folks driving in to tailgate even if they weren't going to the game because it was so fun