Why do OM fans act like they just won the CWS after winning one regional game?
Because they haven't actually been to the CWS since the Nixon administration...
For everyone in their fanbase under 45, they've never actually seen UM make it very much farther than they are right now- so, in a way, what you're seeing is how UM celebrates their pinnacle of college baseball success.
It's going to be funny watching them celebrate actually getting to Omaha when they do eventually get there in the (hopefully distant) future. I fully expect to see grown men dancing naked in the streets of Oxford.