Here is how I see this:
Gus made fraudulent claims in regards to training with GM Chan.
Those claims have been shown and proven to be fake, ie: Gus is a fraud in regards to those claims.
Gus claimed he was a fighter and can fight and has fought many times.
Evidence shows that he is, at best, has mediocre fighting skills. So, while he MAY have fought, unless he was fighting really bad fighters, he probably lost most of the time.
Gus, that I know of, has not produced any students that are recognized fighters, so it seems he can not train fighters either.
SO, what we have is a person that made fraudulent claims in regards to his MA credentials, has mediocre fighting skills and has NOT trained anyone to a level of recognized fighting skill.
And then we have Dave:
Legit training and GM Chan and a few others as well.
Has trained and coached at least national level fighters.
I have not see the video in which supposedly Dave was beaten in a Sanda match.
I can say this though, I don't ever recall Dave referring to himself as a fighter, but as a coach/teacher and I do know that he spars full contact and from what I see in this training clips, he seems to know and move like a fighter.
Far better than Gus that is for sure.
The main issue though is quite simply that Gus has passed himself of as something he is not and has been caught and, well, you can't defend that.
Psalms 144:1
Praise be my Lord my Rock,
He trains my hands for war, my fingers for battle !