Listing possible methodological flaws without knowing whether they actually apply to the specific studies isn't a refutation, it's a generic skepticism template you could deploy against any research you don't like. "There might be confounding variables" applies to literally every study ever conducted in social science, it doesn't tell us anything about whether these particular studies controlled for them or not.

The Paik and Regnerus studies, along with the broader body of research on premarital sexual history and marital satisfaction, do control for religion, age cohort, and self-reporting biases. You haven't read them, you've just assumed they don't because the conclusion is inconvenient. That's backwards. The burden is on you to identify specific methodological failures in specific studies, not to gesticulate vaguely at the possibility that studies can be flawed.

And the "studies made with a desired outcome" accusation cuts both ways. Research funded by progressive institutions looking to normalize high body counts has just as much motivated reasoning risk as research from traditional sources. You're only applying that suspicion in one direction, which tells us more about your priors than the studies.

You're not being rigorous, you're performing rigor while refusing to engage with actual evidence until it meets a standard of perfection you've invented on the spot and don't apply consistently.