I guess I overreacted last time this came up. I don't think they're 'wrong' in the sense that what they're doing doesn't work. Shannon and Beckum are bowyers I really respect.
A lot of us have heat treated over coals in the past, because it's just about the first idea that comes to mind. Doesn't take long to realize how good the quality of a deep, long heat treat from coals can be. So it was a bit weird to see someone saying this is a modern rediscovery. That said, what I have seen of their content has been good bow making material. The bows are are well made and tillered.
After everything I've seen, I don't see a reason to put fire-hardening outside of the heat-treating spectrum. We can even call it Shannon fire hardening, but in my opinion it's still under the umbrella of heat treating.
Silicone heating strips are great by the way. I have one with a 0-400 F thermostat. It can easily get too hot. I can still get a higher quality heat treat with the heat gun, but the labor is much less. You only have to check on it every 10 or 15 minutes. Labor aside, I still think coals are the best way to heat treat. The way you can mold the coals around the bows character, or recurves, is really handy