Black and White= Grey

While reviewing the lecture on "Black and White" and the discussion on : How were ideas of universal human rights emerging at the same time as slavery was in full effect?
In brief, it was said that Blacks were slaves because they were corrupted by nature through the environment.
I would like to reflect upon that belief and argue that it is none sense to say that because of the environment that "corrupted" them ( in particular hot and tropical climates) Blacks were lazy, inefficient and unwilling to work- so no matter how many you rights were given to them, they still would not be able to make use of them. This goes beyond a generalization that people from warm places are unwilling to work, not just Blacks. ) What made Blacks from Africa less productive and unwilling to work then settlers in Southern U.S. I think the argument fits just as well for them as well- I mean, it is the hot climate that's corrupting people, isn't it?
Furthermore, I wonder why people who came up with this theory at the time did not look at places like Australia, New Zealand or other places in Oceania (or better yet even in the Southern states in the U.S.). They have warm climates and are able to be working and productive! This idea just seems to be another excuse to put the blame on a population of people that has gone through enough marginalization and discrimination throughout history.

In my view, this only leaves a 'grey' area and should be open to questioning and discussion!