Some Things

For example, I have a friend with dark skin and her nickname is “negra” or “la negra” (black woman) and its a nickname she likes and its pretty common in Colombia.

The same goes, for example, if you would call your girlfriend/boyfriend “fat” that would probably get a horrible reaction. In Colombia, its actually a cute couples nicknames “gordo/gorda”. Its like calling each other baby. 

So before you come to the conclusion that a Colombian is a racist, check the context. Its not the same to say “El negro la cago” (the black man fucked up), that saying “tenia que ser un negro el que la cagara” (it had to be a black man that fucked it up). The first one isn’t racist at all in our context, the second one is an awful thing to say, and by all means direct your hate towards them.