I did one of these a few years ago when I first visited Rio. I'm a gringo with a Brazilian wife.
Looking back now, especially as I've been living in Brazil for the past year, I wonder wtf I was thinking. The AirBnb host suggested it and I went for it in a misguided attempt to 'see how the other side live'. In reality there are a million better ways to gain this perspective than going on a 1 hour trip through a favela.
Brazil could benefit a lot from more tourism than it currently does. Amazing food, people, beaches, dancing...employing the people living in these favelas with stable work. Instead of promoting the sorts of tours mentioned above that treats them like some kind of second class citizen.