The feedback loop is the process by which a system becomes stabilized. Input turns into output, which is then fed back into the input, and so on. The importance behind the feedback loop is that, if you are monitoring it, you can make quick changes to improve your situation.
Think about a singer, for example. A singer tries to sing a certain note into a tuner, which tells her if she has hit the note she was trying to hit. If she is, then she can keep singing that note; if she isn't, then she can use that information to self-correct and eventually get to the right note.
Feedback loops can be extremely helpful in improving one's strategy. The danger is that feedback loops rely on the assumption of a correct tuner - a mirror, an instructor, someone or something that can determine the "truth."
If the tuner is accurate, then you're fine; but if someone messed with it, changing it around, then if you're not careful, you'll find yourself correcting yourself according to inaccurate feedback.
Consider, for example, the pattern behind much of Donald Trump's tweets: Trump hears something from Fox News, which he then tweets about.
If the tweet is popular, then he pushes the idea further, sometimes in the form of policy, regardless of how valid it is. If they don't work, then he'll find another idea from Fox News, and test that idea until he finds one that his base can stand behind.
The point here is simple: gaining feedback from the ground is important, but you must also have a philosophy (what Sun Tzu calls a Tao, or "Way") that guides your activities. You must have principles that tell you what you will accept feedback from and what you won't. You must decide how you're going to win.
It takes huge courage to go against what the feedback gives you, to sing your own note, but costs may be too high otherwise.