"Diminishes his work"? Are you really this stupid?
The entire way Lovecraft writes is based on appealing to archetypes, built on irrational fears and prejudices. The reasons we react to the portrayal of the Old Ones and their servants, the haunting, alien landscapes and the eery descriptions of bizarre geometries have the same causes as the common prejudices 97.5% of human beings have about strangers, about the Other. The entire theme of Lovecraft's work is the external world, full of unknowns (filtered through untrustworthy sense-perception) versus the inner world of instincts and emotions in constant struggle reason. By the end of most of the stories the characters can't even trust their sense of reason and those who survive do so because they reverted to instinct.
If you truly are the PC idiot you just painted yourself as you should not pretend that you like Lovecraft which would be clearly contradictory. Somebody with no prejudices at all cannot by nature appreciate literature, someone like that can never be more than semi-human.
Someone who does not have prejudices is better off dead because their soul is already dead. In any case having prejudices and failing to control them are two different things.
How you can judge Lovecraft or anyone who has racist or sexist thoughts as 'bad people' is beyond me. As far as I am aware he was a private person and mainly stayed at home and wrote, he never lynched anyone or persecuted any individual, and his first wife was Jewish which proves he was able to distinguish between reality and fantasy (unlike many people on the internet).
