So, you can't be wrong about this?
How do you react to eating an apple yourself?
Also, I don't think it's cultural and I suspect it might be hereditary.
Even if I finish first and the other are still eating, it's really only when I didn't eat / not eating that it infuriate me.
How do you know this?
Not only are you passing judgement on something you have zero personal experience with, you even managed to completely miss the fact that the article did not discuss "being bothered", but "fight or flight response".
How do you know that? In fact, the opposite is the case. And having given this issue considerable thought over the years, I'm pointing out where I see this discussion as a bit misguided. Most importantly, psychological differences are largely a matter of degree, not either-or.
It seems to be ignoring the very large cultural factor. As an American who has lived around Europe, Asia, and the Middle East, I've observed a great variation in what counts as acceptable table manners. East Asian culture in particular seems to accept a lot more chomping and smacking at the table, and this seems to be a general complaint among Westerners, not just a few individuals.
Secondly, as with anything else psychological, there will be individual variation. I feel there is too much eagerness to isolate some end of a continuum and label it as a syndrome. For example, I've always found notable the fact that some people can't comprehend why neighbors would be bothered by a loud stereo and others can't comprehend how anyone could not be bothered. Though there is a significant psychological variation there, I would not label either group as suffering from a syndrome.
As for dealing with irritating background sounds, in addition to white noise, I've found earplugs very helpful in some situations. The best ones I know of are Hearos Xtreme Protection.
https://www.amazon.com/Hearos-Plugs-Xtreme-Protection-pairs/...