Anti-Marxist.
The GSE article sums it up well:
>Bogostroitel’stvo, an ethical tendency that arose among Marxist men of letters during the first decade of the 20th century in Russia, which regarded the creative activity of human beings as religious. The proponents of bogostroitel’stvo proclaimed that it was based on the teachings of Marx, which they understood in distorted fashion.
>They aimed at discovering in Marxist theory the key to solving personal problems that are beyond the control of science, such as the fear of death, loneliness, and so forth without appealing to a superhuman force. The representatives of this trend—A. Lunacharsky, V. Bazarov, and to some extent M. Gorky—declared their task to be the founding of a new proletarian religion without a god, which in fact became the deification of the collective and of progress, which are called on to arouse the “complex creative feeling of faith in one’s own powers and hope for the victory of the love of life” (M. Gorky, Otvet na anketu “Frantsuzskogo Merkuriia”) and to link the ideal with reality in practice. The theory of bogostroitel’stvo proceeds from the proposition that every ideology has as its basis a Weltanschauung which unites people in the emotional sense with the “sacred,” which need not necessarily be god. Here bogostroitel’stvo came close to the “positive religion” of A. Comte and the “religion of humanity” of L. Feuerbach. The representatives of bogostroitel’stvo propagandized their ideas in the press (the collection Studies in the Philosophy of Marxism, 1908; V. Barazov, “Bogoiskatel’stvo and Bogostroitel stvo,” in Summits, book 1, 1909). In 1909 they organized a school for workers on the island of Capri, which was called a “literary center for bogostroitel’stvo” (V. I. Lenin, Poln. sobr. soch., 5th ed., vol. 47, p. 198), and later they organized the factional Vpered (Forward) group. G. V. Plekhanov sharply criticized bogostroitel’stvo as a theory incompatible with Marxism (“O tak nazyvaemykh religioznykh iskaniiakh v Rossii.” Soch., vol. 17). V.I. Lenin linked bogostroitel’stvo with the political tactics of the otzovisty (recallers) and ultimatisty in Russia. In June 1909 a conference of the enlarged editorial board of the Bolshevik newspaper Proletarii evaluated bogostroitel’stvo as “a tendency which has broken with the fundamentals of Marxism” (KPSS v rezoliutsiiakh 7th ed., part 1, 1954, p. 222). V. I. Lenin wrote that this tendency objectively coincided with the desires of the reactionary bourgeoisie “to revive religion, increase the demand for religion, invent religion, innoculate the people with religion, or strengthen the hold of religion on them in new forms” (“O fraktsii storonikov otzovizma i bogostroitel’-stva”; see Poln. sobr. soch., 5th ed., vol. 19, p. 90).
>Bogostroitel’stvo did not become very widespread, and its supporters subsequently renounced their attempt to give a religious interpretation to Marxism.
Lunacharsky himself had right-wing views on many philosophical and other issues. That is why Stalin wrote in 1925:
>Here in Russia, too, the process of the dying-out of a number of old guiding functionaries from the world of letters and old "leaders" has taken place. That process was more rapid in periods of revolutionary crises and slower in periods when we were accumulating forces, but it went on all the time. The Lunacharskys, Pokrovskys, Rozhkovs, Goldenbergs, Bogdanovs, Krassins, etc.—such are the first specimens that come to my mind of former Bolshevik leaders who later dropped into secondary roles. It is a necessary process of renewal of the leading cadres of a live and developing party.
The Soviet revisionists "reassessed" Lunacharsky because they hoped to use his incorrect views for their own purposes.