As someone who knows and understands Brazil, its people and daily life better than you guys I would like to offer my point of view on this.
First it's important to understand that Rio de Janeiro is a beautiful city with a perhaps unsolvable problem. And that Rio is a perfect example of what Brazil is, only worse. Crime and violence are everywhere and all the time, it's constant and affects everyone. It doesn't give you a break, no matter where you live. You're a constant victim of it. From millionaire to poor.... the experience differs a lot but it's never a good one. In Brazil corruption, crime and violence is so common that it became part of live. Is normal. And of course the police is severely underpaid, badly trained and overworked. And often part of the problem.
The violence in Rio has civil war numbers and is mostly caused by drug lords. And they are always going at war with each other. The police (both military and civilian police) can't handle that level of aggression and violence. The morros, favelas are seen as territories by these drug lords and they don't ever allow the police to get there without a fight. Police officers die all the time trying to do their jobs. Honest people die all the time. Or are hurt by a gun shot. It's actually common to hear AK47 shots in Rio. This is not your typical urban violence. They have a fucking army trying to take over the city, it's not a fair fight for the police.
This is not a step towards another dictatorship it's simply a much needed acknowledgement that things have gone too far and that it needs to end. People have been asking for that for years now and I'm sure a lot are finally happy. Imagine living in a place where you're constantly in fear? I hope they do a good job and help the people in the favelas to finally have a some peace. Fuck Rio man, they have as much beauty as they have tragedy.