Uruguay does have racism, but as a country without a history of institutionalized racism in the form of colonialism, slavery and racial separation laws (well there was slavery there at one part, but Uruguay was such a backwater in Spain's empire that it never was ingrained) it tends to be a lot less overt and is more about associating darker skinned people either with other countries or with the lower classes in a more subtle way, without the history of dark skin itself being considered a negative thing. It's often in South America that race is incorrectly considered a non-factor, and so casually talking about skin colour isn't really viewed as a big deal.
Uruguay has traditionally been progressive compared to some of its neighbours (they played black players on their international team far before Brazil and Argentina did) but there's still some element of race-denying. Afro-Uruguayans are actually very well integrated and you don't get the race-separation you do in the US or Europe, but because of that individual claims of discrimination are often not taken seriously.
That's why Suarez and the countrymen defending him are so defiant, there really is a lot of genuine ignorance here and no condescending Englishman is going to convince them otherwise.
Racism is everywhere sadly, but how it manifests itself is very cultural and Suarez's actions still to me sound more like Suarez being Suarez than anything racially motivated.