You seem to be suggesting that basic physics would say you can't unbalance someone bigger than you who's attacking you???? I can assure you that's definitely not the case! In fact it's exactly why some of us find it interesting!
(Also I don't entirely get the point of the analogy, because if someone is an immovable concrete block, I can just walk away and I've won from my point of view. It's kind of a boring situation).
I don't mean to imply that it was somehow a prescriptive method of unbalancing, rather to illustrate power differences can matter, that these power differences can be created because you have put in a lot of time solo training that someone else has not (using methods requiring little to no scientific literacy), and that pretty much all of us are starting off severely unbalanced to begin with.
So, learning first and foremost how to unbalance someone can seem rather backwards from that point of view. Learning how to not be a walking collection of imbalances can seemingly undo/invalidate many years/decades of the most well-intentioned and earnest training of most of us, because all someone has to do to point out our flaws is to come in contact with us. There really are dragons out there.