Now you mention it, yes. Perhaps not so surprising though. Margaret's father was the vicar and was presented as an unfeeling tyrant, at least in his dealings with her. His son was a supporter of Darwin's theories as is Robert, and Dorcas is interested enough in Darwin to have him on her bookshelves.
I haven't studied Flora Thompson nor read the books on which LRTC is based (not a fan of Victorian literature though do occasionally dip in and may get round to this eventually) - it's possible she herself was a Darwinian. Certainly Laura, who is based on herself, admires Dorcas so we might assume she shares some of her views?
Or perhaps it's just that Flora Thompson was writing about old values at a time of great change, and focused on country traditions which for the Lark Risers wouldn't have included regular church attendance? We're told more about country superstition and encouraged not to undermine it, if not actually to believe it.