It’s a metaphor. The Abrahamic god is not technically in the sky, but he has been called the almighty father and heaven has been represented to be in the clouds enough times even if technically isn’t that everyone understands what “Sky daddy” means. It’s a derogatory term, sure, that’s the point. The term being derogatory doesn’t make it a strawman though.

It’s an insult and the Abrahamic god isn’t a protected individual so whatever.