Anecdotally, I've noticed a link between religion and happiness for a long time. The most fervently anti-religious also tend to be the most miserable. If there has been one earthly thing that has reaffirmed my faith, it is that.
The other thing I find somewhat peculiar: it notes "nonreligious conservative women" being least satisfied. Really, though, how many of those are there? That combination is usually associated with libertarians and the alt-right, both of which have very few female supporters.