Aggie Jokes are kind of like Polish jokes. They state or imply the stupidity of the subject.
A&M is the school where all the farmers and small town kids went. The city kids all went to UT.
Even to this day, A&M is considerably more rural, less urbane and sophisticated, AND PROUD OF IT. So that’s what that is all about.
UT has the LBJ Presidential Library.
A&M has the George H. W. Bush Library.
Pretty much says it all.