I don't think it's a stunt but Xbox News tweeting somebody elses tiktok and then an entire article trying to sell Series S on it is a little weird.
It's normal for most electronics to survive house fires unless the fire got really bad. They're built with fire retardant plastic and they need to be within regulation. household electronics are usually the cause of fires and their enclosure is built with flame retardant plastic to act as a barrier and contain a possible internal fire, because of this they also protect the internals from an external fire too. There isn't anything special in build quality.