Corporate culture has changed to where instead of handling conflict according to principle (e.g. Harvard negotiation project, getting to yes, principled negotiations etc), today people are trained to out-passive each other, and marshal political campaigns to isolate opposition. (salience, political survival, working the ref, etc.)
The moment you acknowledge that the person you are dealing with is being disingenuous and manipulative is the moment you have lost. That you can see the mechanism critically signals you do not have power, and that you cannot be trusted to "keep the ball in the air."
The typical response to this is, "that's black and white thinking, people have different perspectives and views, which are valuable and legitimate." While that is generally true, different perspectives aren't the problem, nor are they new. It's a minority of people who exploit the agreeableness and civility of others with a small toolkit of negative plays, and who cluster in high-status organizations because they are motivated by proximity to power, but without responsibility itself.
The OP articulates valuable patterns for navigating flat organizations in calm seas. A set of patterns that describe when the knives are out would be a helpful follow up.