Why no reaction like there was for Bahrain?
I make a very clear distinction between Bahrain and any other country, including Brazil, where there is civil unrest or human rights abuses or anything else of the ilk. With Bahrain, Formula 1 was involved
in the problem because it was a subject of protests that led to people getting locked up and tortured. Without passing any judgement on whether the protestors or government were in the wrong, the staging of the race in Bahrain itself gave rise to the potential for violence and suppression or rights. If
it was demonstrated that killing increased in Brazil in the lead up to the race to 'clean up the streets' for it then I would take the exact same stance as I did with Bahrain, which was that the sport should not visit the country. But as of yet AFAIK there isn't any indication that is the case.
The other point I'd raise is that many people within F1 spoke out about going to Bahrain, based on their own moral position and also due to safety concerns. I've never heard them do that about Brazil - yes they make the point that it's dangerous and they run the risk of carjackings and all that, but I've never heard any personnel state that they don't want to go there to race because of it.