Well, no, that's disingenuous at best. No one was being "handed" to them. They were buying them. And they bought them at a price high enough that it incentivized the Africans they were buying them from to get more people they could sell. It's basic economics. If there is a high enough demand, supply will find a way to meet it. Again, it's not that different from the drug trade. Americans weren't going to South America and forcing farmers at gunpoint to grow cocaine. They were just buying it from South American drug traffickers...who were more than happy to point guns at peoples heads to make them grow it.
The point isn't all humans are assholes; it's that if you create a demand, people will figure out a way to find a supply.