Yet often it was his own stubborn and uncompromising nature that defined his life – his choices paint a picture of a man who was unable to heed the words of others. This undendinly antagonistic nature cost him friends, honours and ultimately put him into the dark role of colonialist.

He was "stubborn and uncompromising", which makes him "antagonistic", therefore a colonialist and racist. That's a pretty low bar. I don't think it makes sense to define racism in a way that makes all 19th century naturalists racist.