Possibly bc it's harder to do mold avoidance in the UKThere is also I think more attachment to the mould hypothesis of ME in the USA than UK currently, although I could be wrong about that. Happy to be corrected.
But jot a good reason to deny hypothesis. Imagine that the treatment for me/cfs is expensive and out of pocket. And the poor people said "this cannot be the true treatment , and if it was , almost nobody could afford to do it, so impractical ". It would be flawed reasoning even if sympathetic. I see the same thing with people saying they can't do mold avoidance and that its impractical solution. I agree, having been made broke by it along with many other treatments. Doesn't change the empirical reality tho. If it works it works. If it doesn't it doesn't. we need studied.