Unless one lives in Copacabana, no self respecting Carioca spends any time there. It is one of the most densely populated places on Earth, there are few good restaurants, the hotels (as already written about here) are generally (especially for what you pay for them) bad, and ocean generally polluted.

Here is the difference between Copacabana and St.Louis. In St. Louis generally speaking, everyone drives, and no one walks more than a short distance, other than perhaps one or two specific places, I cannot think of any great alluring areas that any tourist is dying to walk along. Copa OTOH has acres of sidewalks and is next to the sea and is quite alluring to walk along..................which is why a high percentage of people who are new to Rio get robbed. But what do I know, I only used to live in Rio.

Ipanema/Leblon are far safer (and nicer) than Copa, but still "bad things can happen" but just not as often. and yes, beaches out by Barra, etc are a hundred times better and the water far cleaner.