UK/UofL is the rivalry it is because it too goes way beyond sports. For example:

1) Louisville for years recruited by telling recruits that Kentucky and UK were racist and didn't REALLY want black people on campus. Rupp has had his legacy tarnished by this to this day.

2) As a general rule, most Louisville fans in Jefferson County are black or east end white yuppies while the 50% of Jefferson County that supports UK are working class whites mostly on the south end of the city. Most of the UofL groups assume and treat the UK fans, both in Jefferson County and the state, as ignorant, redneck, backwards, racist, hillbillies and treat them with utter contempt, not just in sports but in general. There are hard feelings between Louisville and the rest of the state because of this in every facet of life. For instance, despite Louisville being 20% of the state's population, no Louisvillian has been elected Governor of the state since 1864.

3) Related to the above, the rural versus urban divide and also the fact that Louisville is a wholly Midwestern city sitting in a thoroughly southern state. Most Louisvillians have much more in common with people from Cleveland, Pittsburgh or Chicago than anywhere else in Kentucky, and so there are plenty of opportunities for hard feelings because of the inability of Louisville and the state to effectively communicate/understand the other's point of view about stuff.

UK/UofL, unlike the other rivalries cited, has less to do about sports and more to do about culture and life in general.