BU has a better campus life than Wisconsin-Madison? I am not sure many would agree with that.
As for the overall ranking, forget any ranking that has BU ranked over Wisconsin. It simply isn’t accurate. Wisconsin is considered one of the top 25 universities in the US, full stop. Any ranking that has it ranked out of the top 25 shouldn’t be taken too seriously. Wisconsin is a founding member of the AAU and remains one of the best universities in the country.