La Carpio is viewed by most people in San Jose as somewhere you don't want to go because it's dangerous. It's not. I haven't spent a lot of time in the community, but in general it doesn't seem less safe than most areas of San Jose, just poorer.
Most Ticos will also tell you that La Carpio is made up of all Nicaraguans. (For many Ticos, Nicaraguans=Violence.) They are wrong. Many Ticos live there, it's just that the general population would rather live in denial of the fact that living conditions can actually be that bad for Ticos in Costa Rica.
Rather than continue describing the relationship between Costa Ricans and Nicaraguans I'll just say that it's very similar to the U.S.-Mexico relationship. Nicaraguans immigrate. Nicaraguans work in a lot of jobs that Ticos don't want (like coffee picking). Violence occurs. Ticos blame Nicas for violence. Ticos notice the presence of drugs in the city. Ticos blame Nicas for drugs and drug violence in urban areas. Ticos pay a lot for good health care and see people that they assume to be Nicaraguans in clinics. Ticos blame Nicas for stealing their high quality health care which isn't available in Nicaragua. Nicas continue to immigrate to Costa Rica because, even in shacks like you can see in the pictures from La Carpio below, Nicaraguans have better lives here than they ever had in Nicaragua.
I happened to be inside the clinic where we hold rehearsals when I took these pictures so some of them are from behind a fence.
As you can see in the background here, as if the lives of the residents of La Carpio weren't tough enough already, they are lucky enough to have high-voltage wires running through the middle of their community which is pretty dangerous. But of course, as long as the wires are there, the residents will take advantage of their presence by stealing electricity from them, which is Extremely dangerous since it involves splitting the wires that are in the air and running them into your own house.
La Carpio is also lucky enough to be a neighbor to multiple landfills (and a cement factory - health problems?) and as such they constantly have garbage trucks driving through the community. How pleasant. Of course, the passing garbage trucks don't do anything about the piles of garbage lying on the sides of the streets in La Carpio, they just drive on by, just like the majority of Ticos who continue to ignore the community.
La Carpio is also lucky enough to be a neighbor to multiple landfills (and a cement factory - health problems?) and as such they constantly have garbage trucks driving through the community. How pleasant. Of course, the passing garbage trucks don't do anything about the piles of garbage lying on the sides of the streets in La Carpio, they just drive on by, just like the majority of Ticos who continue to ignore the community.