Why will unscriptural, man-centered, culturally conditioned, over-contextualized worship undermine confessional orthodoxy? Because worship by its very form (which ought to be according to spirit—uppercase and lowercase—and truth) communicates certain things about the nature of God and man, thus theology proper and anthropology can’t help but be warped by unbiblical worship. Theology proper and biblical anthropology are the foundations of soteriology, which will also be warped by unbiblical (e.g.: revivalist or sacerdotal) worship.
Why will unscriptural, man-centered, culturally conditioned, over-contextualized worship undermine biblical, presbyterian church government? Because free-form, optional, variable worship forms suggest free-form, optional, variable ecclesial forms…or little form at all. And when worship is no longer led by ordained elders, government by ordained elders seems less plausible. Presbyterian order is not hierarchical, but neither is it excessively horizontal. Rolling it out too thin leads to its disintegration.