If you actually read my comment, you would know that it said. And it said none of that. Hint: the part that's in parentheses is part of my comment too.
Let me flesh it out for you. I said, "The European colonies in America joined the African slave trade because the supply of American Indian slaves was being exhausted, as a matter of fact." Which means I'm not only aware of the trans-Atlantic slave trade, but I even outlined the specific reason why slavery of American Indians wasn't sustainable and why the North American colonies had to engage in the trans-Atlantic slave trade to begin with. The fact is, west Africa had more slaves to sell.
Speaking of Brazil, if you start at the end of the second paragraph of Wikipedia's article about slavery in Brazil, it says the exact same thing happened in Brazil:
Starting around 1550, the Portuguese began to trade
enslaved Africans due to two main reasons:
* The unenculturated indigenous peoples deteriorated
rapidly, and became increasingly wary of the
Portuguese, thus, obtaining new indigenous slaves was
becoming harder and harder.
I try to play nice on Hacker News, but when people don't even read and comprehend what I write, and then accuse me of saying the exact opposite of what I said, I get a little annoyed. Part of common courtesy is to understand and respond honestly to others, and frankly, you've failed to do that.