Subsonic said..
I don't recall the part of the video where he had a race sail on a free ride board? But all the same, much the same as you using a trad slalom board for windfoiling, he has the experience to recognise what effects that will have on the ride.
@Subsonic, I said "freeride setup". Look at the pictures from the video, this very much looks like a freeride setup to me.

And of course you are right, be it an ordinary slalom or free race or freeride board - the foiling experience with a board that's primarily meant for windsurfing is not the greatest, and I doubt it ever will be, or that it should be. A dedicated foil board is much much better for foiling.
That said, I still think that most of his frustration with the early foiling gear was tied to the gear selection they made themselves - having huge boards and huge rigs, with the intention to go fast, and then using the foils that did not live up to the expectations. This is also why I think the suggestion that brands should offer ready made packages is a slippery slope. Foremost, there are too many different foiling disciplines, the ultimate speed seeking people are just one fraction. Secondly, there are foil brands that don't build boards, there are sail brands that don't build foils, there are board brands that don't build booms etc. Telling newcomers that they should only be looking at the gear that's offered by these brands that make a complete package is kind of limiting.
Therefore, I find it's much more sensible to steer beginners to shops and communities who can help with the gear selection. Ultimately these are the places that can put some work in, find out what combinations work the best for serving their clients, create content, offer lessons, take regional nuances like the availability of the gear by certain brands, etc. into account, and provide the best support.
There has been excellent freeride / free wave / foil style foiling gear available for ages now, so it's a bit unclear why such a racing or fast freeride foiling oriented video now.
And again, foiling at the beginner stage, when just introducing newcomers into the foiling world, does not necessarily have to involve huge race sails and huge wide boards. I'd suggest to keep it simple. Well, a plain simple 300 euro beginner dacron cloth sail as in the following clip is more than enough for foiling. Ultra light weight and feel, and performant and fun enough.