You may or may not of noticed that humans and horses are different in a lot of ways, again, observation of actual long term results in horses probably trumps twitching muscles on humans, it's the whole apples and oranges again.
No one is asking you to try it, so why worry...
You would need long term observation of TWO groups: those strapped, and those not strapped, with everything else held equal. Your observation is based on horses "strapped everyday, and exercised, and fed a balanced diet built from the ground up". To show strapping is effective, you would need to compare them to a group of horses that were cared for equally, "exercised, and fed a balanced diet built from the ground up", but who were in worse condition with strapping/not strapping as the only variable.
Human muscles and horse muscles and muscles of other mammals are not all that different. The twitching done with electrodes in humans would involve a much greater number of twitches done for longer periods of time. If not effective there when compared to exercise, then there isn't much realistic hope that strapping a horse to get 100 twitches a day will do anything that couldn't be done better by walking for a couple of minutes.
I'm not worried. However, there has been a lot of stupidity that stays around in the horse world forever, such as not allowing horses to drink after exercise, or not to cool them off with water, or the 20% rule for weight carrying by horses. It is completely reasonable to bring any studies available to bear.
As massage, strapping may work well. But the video claims it will build muscle, and there isn't any good reason to believe that, and a lot of info that would contradict it.