Criticizing a writer for not having the same social mores and sensibilities is pretty weak. It opens a huge can of worms for pretty much all writers of note. Shakespeare for Shylock, Twain for Nigger Jim, Conrad for the Nigger of Narcissus and on and on and on.
That being said, there has been much written about HPL's racism by some brilliant writers. I recommend Michel Houellebecq's "H.P Lovecraft: Against the World, Against Life" which has a chapter addressing his racism and argues that it was part of the central motivating force in his writing.I just re-read it (starts on p. 105) and it's a great read. After all, the Mythos are the perfect Other. So if you enjoy some of his work, then you are part to the same types of thought as HPL. :O
Anyway, great art requires great understanding in order to comprehend. It's fine to read and enjoy the work of HPL on a surface level but disliking it because it makes you uneasy because of his antiquated racism shows that you need to dive deeper. You can enjoy his work and acknowledge his racism at the same time.
I'll have to check that book out. I will say that I think his racism went a little deeper than some of the authors you cited, or at least in my reading it seems to be deeper than using a term that was socially acceptable at the time of writing. I tend to agree with S.T. Joshi in his assertion that Lovecraft tended to go further than other authors of his time period.
That being said there's no doubt that his views shaped his writing, as it does for all authors. And nobody can deny the impact his writings have had over the years...and will continue to have for years to come. Re-reading some of his writings with my eyes opened to the almost autobiographical nature of some of his characters, in terms of some of the hardships in his own life, certainly can give you an appreciation of where he was coming from.
I certainly don't throw him out as an author. He is by far my favorite horror author, if you can even really tie his writings to a specific genre.