Come on man. While "it was totally genocidal" is wrong, "never any genocidal policy" is equally wrong, and you must know that.
Well by genocidal policy I would interpret a policy to deliberately exterminate the natives. Indeed, this never existed in Portuguese America. Quite the opposite, the Portuguese wanted to convert the natives, marry them to Portuguese settlers whenever possible and basically turn them to good subjects. Indeed many Portuguese nobles, including the most important one of all, had Brazilian Indian ancestry.
Now, does that mean that the interactions were good for the natives? Of course not. Indeed some tribes, which were more hostile to the Portuguese, were completely annihilated. The spread of diseases was also catastrophic, and often the Portuguese diseases would reach Indian tribes before the Portuguese themselves, with devastating effects. It seems that there was a relatively sophisticated Amazonian civilization that was wiped out this way, without any contact with Europeans.
But this very different from a "genocidal policy". The Portuguese knew they were a small and weak country and could never control Brazil on their own. For as long as Brazil was portuguese, they did not allow other Europeans to settle there. They much preferred the Indians and mestizos, which they y considered more loyal. Mass non Portuguese immigration only begun after independence, and that's when Brazil ceased being heavily Indian and African and got its modern face.
So I'm not downplaying the cataclysmic effect of colonization on Brazilian Indians, I'm just stating that there was never a policy to wipe them out.