I don't doubt that, but for many of us, it's a matter of degree. Like I don't mind soft conversation in the background, and I prefer soft bluegrass over dead silence... having SOME sound helps me focus and stay on rhythm mentally. If someone eats lunch while I'm working, I probably wouldn't even notice it, and even if I did, I'd just be like "What's for lunch?" And then go back to work.

But for my friends with severe misophonia (self-diagnosed, for the most part), hearing chips crunch or lips smacking will drive them out of the room in abject fury. It is, according to them at least, uncontrollable and unavoidable and it turns what would be "mild annoyance" for most of us into "severe anguish". At that point it's not even about losing some productivity, but being driven into such severe discomfort that you can't physically be in the proximity of the sounds anymore and you start to hate the other person who's caused it, and it all just unravels from there.

There's a huge difference between that and "oh, well, that construction noise outside is kinda annoying, I hope it stops soon".