He's trying too hard to over-simplify it. The Q you need to ask is WHY you take a stance. If it's to block, then it's different than someone who needs to be able to pivot, dash forward, backward, laterally, etc. And, needs to change their footing for what is happening with the upper-body. Boxers are doing an incredible number of offensive and defensive things with their upper-body that require changes in stance. I really don't like this analogy as it distracts from the principles of boxing.
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