May I ask where you have the info from that Mt. Rushmore is gonna be a small wonder and arrives with Fascism?
And on topic: Practically every civ (or better for artwork, etc.) has its own culture, so I find it a bit tragic that everyone has to build Mt. Rushmore or Oxford University. It'd be much more fun if America(n culture group-civs) builds Mt. Rushmore, whereas the African (or Middle Eastern) civs build 'Kilimandscharo'. Or even better, the English build Oxford University, the French the Sorbonne and the Egyptians the 'library of Alexandria'.
Onto the effect, well, historically I do not see anything besides culture and tourism, but gameplay-wise it could represent the development and thus really something against Fascism... We'll see.
mitsho