christianity in old magickal grimoires - sometimes possibly just a cover?

ive always been a little annoyed by the elements of christianity in older grimoires, thinking that since christianity seems to be made up (archeology/fossil record+dna/theory of evolution, "bible unearthed", etc), then doesnt this in a way discredit everything else in the grimoire?
i used to wonder about this until i read this in joseph c. lisiewski's book ceremonial magic and the power of evocation:

Despite their authors' long-winded Christian stance and admonitions-a socially proper and politically correct carry-over from the days of church punishment if the grammar fell into the hands of an Inquisition tribunal-such texts have their practical use.

the appearance of a christian framework might have been necessary to avoid trouble in times where witches and mages were tortured and burned/killed?