Surely what it comes down to is that we live in a diverse society and, if we want to be able to go out and about enjoying life, we have to put up with things and people we'd rather not on a fairly regular basis.
Unless you want to ban everyone over 6ft, everyone over a Size 20, everyone who makes noise (voluntary or involuntary), everyone who eats and most small children from the theatre, you're never going to achieve the ideal environment for everybody.
Personally, I would much rather see the show and be squashed than be sat behind a tall person and have my view blocked. I would much rather hear the show and be squashed than be sat near noisy people. Because I am skinny, don't suffer from a pain disorder and don't have sensory issues but am very short, sensitive to noise, hate food smells/noise and love (almost) all theatre.
Someone else might be able to cope without a good view or with a certain amount of noise as long as they were comfortable.
In a public place where anyone has the right to attend, no person is guaranteed the environment they would like or have paid for. The experience can be spoiled by any number of things that are cause by (though probably not the fault of) another member of the public with an equal right to be there. It's pot luck and part of being in society.
I just try to remember a very powerful lesson I learned from a thread years ago about whether a child with special needs should have left a theatre production because he was making very loud noises and the OP felt their ticket money was wasted - a person whose experience is spoiled by someone doing something they can't help is only going to have that one experience spoiled. The person who 'caused' the issue has to put up with judgement, disapproval and guilt every time they try to engage in a normal social life