Brazil is a huge country and any large country having an outbreak is obviously bad for the world. This much is clearly self evident from the initial outbreak.
It's certainly bad for the people there, but how is it bad for the rest of us? It's a pandemic, it's not like failing to contain the initial outbreak.
I'm not saying this would be a good idea, but Brazil is unlikely to be able to adequately vaccinate its population in the next year. This should be a consideration, as it was in March 2020 in several European countries before they adopted the chinese strategy.
Herd immunity is applicable to immunity and susceptibility in a population. https://academic.oup.com/cid/article/52/7/911/299077
That's obviously false, given that we are observing many meaningful variants without anything close to herd immunity.
Each person infected is an additional chance of a variant with antigenic escape, let alone vaccine escape.
What is scaring the world the most now is the possibility of a new brazilian variant that can escape current vaccines. That would move the whole world to the beginning of the pandemic again.