Is the word the only issue, or the sentiment it is conveying? The passage and others in the book are not made ‘bad’ just because of that word.

The sentiment Joseph Conrad expressed in his books is that colonialism is evil and corrupts the souls of anybody who participates in it. If you can't read his books because you can't get past the dated language he used, then you are rendering yourself culturally impoverished.

Have a look at criticism by Chinua Achebe and the latter rebuttals. It’s more complicated than you are making out.

I have, and it isn't. Have you actually read any of his novels, or are you relying on Achebe to do it for you?

Yes. I’m surprised you’d say the issues are simple. The criticisms explain the problems better than I do, which is why I suggested reading them. Have you read them?

I read HOD a couple times, which is related to European subjugation of Africa

Nowhere in it do I find any sort criticism of the harms that were done. He describes the awful conditions in the Congo, but does not necessarily oppose them

The language he uses to describe the Africans is hostile at best. A poignant example is the part about the "insolent black head" peaking through the doorway while Kurtz lay dying

Not saying that Penguin should've removed his name because that's a different argument, but I have no idea how/where you're getting anticolonialism out of Conrad and I'd genuinely like to know

Edit: what did I get out of HOD? The death of God. Kurtz goes out to a corner of the Earth that was yet to be corrupted by capitalism. Marlow goes on a journey with no message in particular, he's a witness to the historical event