Frischknecht or whomever winning a World Cup or any race does not confirm the effectiveness of suspension stems for off road performance
unless you are comparing to one of my locked-up vintage Manitou forks with ‘melted’ elastomers
Frischknecht said that he and his teammates were faster than the riders on bikes with suspension forks.
Winning a world cup doesn't mean winning a single race. It means that Fritschknecht accumulated the most wins in dozens of races over the course of a year (1993) while using a Softride stem, against fields of competitors who were all riding bikes with suspension forks.
That would seem to "confirm the effectiveness of suspension stems for off-road performance." If not, what evidence would be convincing, in your opinion?
If it's simply that you don't like the idea of riding with a suspension stem, that's fine. Just say so.