[vezzy-fnord]

Even Catholics are quite inconsistent. There's the oddly progressive Old Catholic Church that split off from the mainline at the turn of the 19th century over papal infallibility. There's the sedevacantists who think all Catholic activity after the Second Vatican Council is illegitimate. Even among those, they can't agree whether or not popes after Pius XII even can be legitimate if they recant their alleged heresy, or if it's all lost. The latter conclavists thus actually get to elect their own popes (who are antipopes from the perspective of the mainline).

Then amongst traditionalists and others, they can't agree on whether or not classical liberal principles are compatible with Catholic doctrine or not. Christopher Ferrara and others thinks that all of United States history was a giant mistake and that we should revert to pre-Enlightenment theocracy, Tom Woods and others argue that liberalism is what Catholicism logically leads to.

No, there isn't much certainty about overarching principles. That you can't conduct your own life based on secular morality is false. Most people don't conduct their lives on any explicit morality. The ones that have ever pondered these questions in depth have always been a minority. Everyone else has only trickled down breadcrumbs from some clergyman, or ignored it.