He might have been a social reactionary in some ways, but he was also a futurist and a man of reason if not of letters. Lovecraft saw life as a battle between science and charlatanry.
In fact, the oldest surviving writing of his — in 1906, at age 16 — was a scathing letter about an astrologist:
"To the Editor of The Sunday Journal: In the Journal for May 17, I notice among the letters to the editor a set of astrological predictions for 1906. Passing over the fact that astrology is but a pseudo science, not entitled to intelligent consideration, I wish to call attention to a striking inaccuracy in the aforementioned article. Its writer mentions a transit of Mars over the sun in July. Of course, as Mars is a superior planet, or one outside of earth’s orbit, it cannot transit over the sun."
His attacks on astrologers just got better and more outrageous the older he got. In 1914, he began a flame war in his local newspaper for which he also wrote a column, railing against a local astrologer’s predictions:
"No sooner do we deem ourselves free from a particularly gross superstition, than we are confronted by some enemy to learning who would set aside all the intellectual progress of years, and plunge us back into the darkness of mediaeval disbelief."
In The Call of Cthulhu 12 years later, he flips that around — suddenly it is “the sciences” that have harmed us little but will eventually make us “go mad from the revelation or flee from the deadly light into the peace and safety of a new dark age.” On face value, they seem like different arguments, but Lovecraft is more subtle than that, and is making a finer point.
Eventually, Lovecraft got so frustrated in that particular letter war in 1914, he resorted to satire under a pseudonym borrowed from Swift to bash a famous astrologer. Suddenly, Isaac Bickerstaffe, Jr.’s letters to the same paper supported the astrologer and bashed Lovecraft, all while making even more outrageous predictions for the future than the real astrologist:
"Last and more terrible of all, the collusive quarternary trin of Mars, Mercury, Vulcan and Saturn, in the 13th progressed house of the sign Cancer on Feb. 26, 4954, stands out as plainly as the handwriting on the wall to shew us the awful day on which this earth will finally and infallibly perish through a sudden and unexpected explosion of volcanic gases in the interior."
Of course, less than two weeks later Isaac would announce in another letter he had solved that problem by considering a recently discovered comet:
"From all of which we may easily deduce that on June 29, 4898, or nearly 56 years before the great catastrophe, the comet XY4 will harmlessly encounter our terraqueous globe, safely taking away on its tail the entire human race!"