What is stated in the regulations isn't the be all and end all. How they are interpreted goes to enforcement and if need be to the courts. Whether or not dispatching an already crippled bird is defined as 'hunting' would be the question. Generations of hunters wring necks. It is not some hidden dark practice.
If there was some surge in ambushing birds by hand then I suppose we would hear about it from the COs first who might try to make it a case. If you recall, the regulations against primitive methods of hunting only came up because of that fellow who got into social media for killing bear with a spear. When it was on the down low it flew beneath the radar and so was legal. It is interesting the "except by" is there specifically limiting it to those methods.
I also stand corrected about the methods not showing up in the federal regulations.