This is a wayward argument.

You're arguing from the quote that 'it's other than disease' and then two sentences later that it was, but due to 'persistent contact needed for conquest'.

None of this adds up to a coherent argument.

If Aboriginals weren't dying en mass from disease, then what from? Because we have crude records of interaction. There were very few violent fights between Aboriginals and newcomers in Canada, for example.

And where is the evidence that Colonialists had 'consistent, closer contact' in hew New World, than in Africa?

I'm all for more nuanced history, we're learning stuff every day, but I think a lot of it is also speculative, and ideologically driven.