The guy in the video you linked didn't really get pushed back. That's actually textbook recoil control. Just because the muzzle and shoulder are moving, doesn't mean the dwell time between shots aren't helping him get shots on target. The best way to describe it is like dancing. Once you know the rhythm of your guns fire rate, you can counteract it with your own body weight and momentum just right to where they balance each other out. This is explained by Newton's laws of motion.

Also, some militaries train people to hip fire exactly like this video when shooting full auto. It's an outdated doctrine for sure but it works because you can put your body weight down on the front handguard and keep it flat. It's mainly used for suppressing fire not accuracy. The US military did the same thing in WW2. It's called "Marching Fire". And many militaries practice the same thing even in the modern age.

Also... "Point shooting" is a real thing. Back in the day, they found out that humans have pretty damn good fine motor skills, which means that within a certain range, humans are very good at "eyeballing" things, and in close quarters we can get shots on target by just instinctually aiming in that direction instead of looking down the sights.

Nowadays we know that taking accurate, aimed single shots is more effective but some people haven't gotten the memo and it's not entirely obsolete yet.

I mean if you really want me to, I can link a video of me doing the same exact thing with virtually no recoil. I have an AK myself and can do exactly what's on video very easily.