I mean, even if a Christian is an evolutionist (as I am) and accepts that the Earth is 4.5 billion years old and the universe 13.7 billion years old, he is still, in a broad sense, a “creationist,” though not in the problematic sense associated with young-earth creationism.
The Big Bang itself is highly compatible with the original act of creation ex nihilo. That is precisely why it was initially resisted by many who believed that science, in order to be truly scientific, must somehow flatly contradict every Christian doctrine.
Arthur Eddington even said “Philosophically, the notion of a beginning of the present order of Nature is repugnant to me.”
So there is that.
I am also quite convinced that the insistence on the multiverse theory is, at least in part, a way of neutralizing the notion of a beginning to the present order of nature.
I am not saying that this is all there is to it, but I do think there are significant theological—or, perhaps more accurately, anti-theological—motivations behind the appeal to the multiverse. After all, not only does the Big Bang suggest that the universe had a beginning, but the likelihood of the present state of affairs being exactly as it is appears unfathomably low.
The multiverse, then, “solves” two problems at once for materialists.
First, it cancels out the supposedly “repugnant” idea of a beginning .
Second, it addresses the problem of the universe’s constants and fine-tuning by proposing that there are an infinite number of universes (each with different constants) most of them unfit for life. We simply happen to live in one of the few with the “right” conditions, much like a dice being rolled billions, if not trillions, of times.
It is hard not to notice how “convenient” this theory is for many.