Here are my thoughts. The only reason Taylor Kelley thinks that TKD techniques aren't functional is because he doesn't have a deeper understanding of TKD techniques and how to correctly apply them. He sees a technique in TKD, doesn't understand it, and because of that he thinks there is a "hole" or "gap" in the system.
The fact that people from other martial arts systems can see functional techniques in TKD and can tell you how it works and how to apply it, but Taylor Kelley cannot see what they see or even understand it, should be a big red flag for anyone trying to support his idea of "Functional TKD" This guys seems to have no problem in understanding his TKD techniques. This is what it looks like when someone digs deeper into their fighting system.
This is what Taylor Kelley look like. What you see him use in light sparring is the limit of what he understands. I don't care what he claims as martial arts experience because this video shows the truth in his understanding of TKD techniques or any other martial art technique he claims to know.
I know without a doubt that some of those techniques in that first video are valid and can be used in a real fight with no problem. I also recognize that some of those same techniques are found in Kung Fu systems and Japanese martial art systems. I have yet to see him demonstrate any significant fighting or self defense ability beyond his free sparring video. He has never made a video explaining the application of a technique.
Many people hate on Forms as well and then use Muay Thai as an example of learning without form.
Well here's traditional Muay Thai Form. The same art that he champions uses the forms that he so much hates.
The main problem is that he insults everyone and is highly disrespectful of others. Then when someone criticizes his approach with the FTF idea, that person suddenly becomes a hater. Yet he's the one with hundreds of videos bashing other martial art systems. In addition to that he then tells people "How to deal with a stubborn Korean Master" and the solutions that he gives aren't only disrespectful but they are backstabbing in nature. This is the type of person that would head the FTF. He is the person who will set the tone and morals for the organization and it's behavior. People who will join his project will be people who make the same assumptions and see nothing wrong with the way that he insults others.