I definitely have some form of misophonia, but that doesn't mean everyone is therefore a closed mouth chewer. I rarely have any issues with my wife or MIL but my mom/dad/brother would definitely have their mouth open between chews, like they had a giant wad of big league chew instead of a normal bite of eggs. My sister was not like this. My old boss always chewed gum with open chomps.
There *is* a difference. And audio aside, seeing people's food mashed in their mouth is kind of gross.
Loud bass has the same effect on me and was a huge rustler in college. I think the human component is the key in these sounds being so annoying. I never hear anything in nature that bothers me, even when there's a shit ton of bugs ( unless it's a lone cricket when trying to sleep).