rotational dynamics - Why a body always rotate about its center of mass?

I found after searching that This question has been asked before . But all the answers were not convincing.

Suppose I have a body which is free, not constrained always rotate about its center of mass. Why is that so? A convincing answer that I found was that in most cases moment of inertial about center of mass is the least and that's why the body rotates about the center of mass.

But I ask it again with hope of the question not getting closed and getting a better succint answer.

Edit

I was thinking that motion about the COM is the most stable one and the rotation about other points degenerates. I don't think it's right . Is it ?

Answer

You presumably already know that in the absence of external forces, the center of mass of any collection of particles moves at a constant velocity. This is true whether they are stuck together in a single body or are just a bunch of separate bodies with or without interactions between them. We now move to a frame of reference moving at that velocity. In that frame the CofM is stationary.

Now suppose that the particles are indeed stuck together to form a rigid body. We see that the body is moving so that: 1) the CofM remains fixed, 2) all the distances between the particles are fixed. (This second condition is what is meant by a $rigid$ body after all).

A motion with these two properties, (1) and (2), is precisely what is meant by the phrase ``a rotation about the CofM''