I took it as he was just explaining the concept of it without getting into the details of it. It's sort of how I cover things when I'm spoon feeding people Kung Fu. I recently put in a video of me working with a student on the application of the technique and I only decided to take one part of the technique to cover.
Most strikes to the groin are kicks and if you aren't careful then you'll break your arm trying to block kicks that low. The biggest risk which made me think that it wasn't a block is that to block like that leaves your head exposed so I can make a kick look low, then have it rise and kick you in the head. If you were to try and use that low block as it's shown in a real fight, then you'll get knocked out. You would have to abandon the concept to use it that way in application. However if you keep the same concept that I mention, then you can perform the technique almost exactly as you would in the form.
This is more in line with how I see it in Jow Ga Kung Fu. You can literally see the same shape of movement of that TKD low block that is done in the form.
This is also in line with what I know of "low block" which is really not a block but a strike. The reason why is because he moves out of the way of the kick and then he punishes the offending leg. The first downward block that he did on top of the shine will break your arm. I'm 100% sure of that as I almost broken mine like that when I screwed up on the "low block". I came down on the kick instead of moving out of the way first and then strike. It was just a natural reaction when I did it. It blocked the kick but I paid a heavy price.
I wouldn't recommend it unless your arms are like solid steel and your opponents shins are like wet noodles.
This is an interesting one. I don't know if it works but it's definitely not a block
On a personal note. I would never intentionally use a "low block" to block a kick like this guy does.
By the way. it's going to be a long discussion between you and me. So I guess I'll just go down the list and hit the next "block" once we juice everything out of the low block.