I suppose compared to the native American population - as people from Africa already had been exposed to microbes and diseases that wiped out swathes of the indigenous peoples of the Americas - people from Africa were stronger and able to work more (before they died. Many places people were just worked in to the ground as it was cheaper to ship over fresh supplies than to look after your fellow human beings in a decent way).
They were also better acclimatised to work hard in the heat than say indentured workers from northern Europe.
But equally, yes, the seemingly limitless supply of slaves from central Africa (a loosely applied term just now) and the fact they were already rounded up and clear to be shipped off was a very important factor.
The truly horrible thing to consider is how easy we dismiss the suffering of other people if we feel we can justify it.
I do see what OP means when referring to «White behaviour» as the last massive empires the last 500 years have been mainly European empires with White men excelling in inflicting atrocities on others in the pursuit of financial gain.
Witness the havoc in Sudan now; still an echo from colonial times even if there are New powerstructures at play now.
It isn’t White behaviour though, as such, as others have pointed out more eloquently. It is greed and opportunity. And then belief systems implemented to justify the actions.
But the consequences of these belief systems have for the last centuries been felt most keenly by people with Brown or Black skin, and that has to be acknowledged when we discuss our histories.
History was a «gentleman’s» subject for a long while, who investigated whatever they were interested in and published what they felt was important, which was stuff about men from Europe, largely. Luckily now it is a lot more diverse, but the sort of mainstream published history is still a lot about European History from a European/Western perspective. I’m glad that’s being challenged.