That's really interesting. I haven't read any Machen but for Lovecraft I think it's the entire universe, man and cosmos alike, that's both savage and indifferent to "civilized" life, with humans being a chthonic* product of that universe and thus inheriting its savagery.

Most definitely. And when I first encountered Lovecraft as a teen I'm sure that's how I read it, with maybe the vaguest sense that the narrator thought certain types of humans were "less savage/more civilized" than other types of humans.

Given that Innsmouth is somewhere in Rhode Island or south shore Massachusetts he was almost certainly talking about people of Portuguese descent. To Lovecraft they wouldn't have been "white."