Just what Conrad was up to in his Heart of Darkness, 1899.
He opposed the massive hypocrisy of imperialism.
But not necessarily imperialism, nor even colonialism, judging just by this book.
Via this book, he and white people in general have nevertheless been angrily denounced for racism.
As to the latter, racism - specifically, the idea of the racial inferiority of blacks to whites - has historically been used as an excuse for the most unspeakable crimes and the most inhuman rapacity.
That doesn't make it false, though it may well be that.
And it is certainly possible Conrad believed in the racial inferiority of blacks without for a moment buying it as an excuse.
In any case, he was a profound pessimist, atheist, amoralist, and even nihilist.
And a very fine writer.