I say why not both,

it is 'uniquely evil', because of it both being extraordinary material product of 'geography and circumstance', which encourages it, and what the perpetrators decided to do with it (whom it encouraged)

Any human, let alone group, in my opinion can be as uniquely good or evil to one another, but when they are enabled by giving them the material tools they need to reshape the world in their favor, they can show themselves to be that force of good or bad.

If a system that encourages dispossession and destruction of past modes of production and livelihoods, to make efficient exploitation of people's labor for Capital, creates a group of people who uphold such designs, especially at the expense of others

Then I tell you, while those people may be uniquely evil than the average person, at the end of it, they're not more evil than what the system does.