Oddly enough, I don't claim to really love language for the sake of language, but it's pretty useful in my day to day so I try to use it well. I like your post, so, in the spirit of negotiation let's use the term baseline instead of rules.

The bulk of educational and informational works on the English language gives us a kind of baseline for our written language. When someone deviates from that baseline, most of the time we can still understand them because we can see how it differs and can infer their intent based on context and that baseline.

The dictionaries, style guides, and grammar texts that give us our baseline exist to facilitate written communication, not stifle it. They're the result of hundreds of years of these kinds of negotiations, not just arbitrary choice as so many people claim. Good grammar isn't just a cudgel to beat the creativity out of kids, it's the benefit of centuries worth of experience and study. Just as new ideas shouldn't be dismissed out of hand, we also shouldn't disregard past practice simply on the basis of it's age.

Baselines do change. But it's a slow process, not every popular new deviation will stand the test of time, and many antique forms are still present in our modern language. Think of it like scientific progress. Some ideas are validated by experimentation, others are proven wrong. Our understanding of the universe is more complex now than centuries ago, but there are still numerous constants that have been proven time after time. Our language has grown more complex too, but that doesn't mean that some very old ideas about how to communicate in writing aren't still useful today.

But you're very, very right about shame and reactions, and I'd be dishonest not to admit that. It's too easy for armchair grammarians to treat language as if it exists in a logic vacuum separate from human emotion, and that's simply not the case.

Omitting a period from a text isn't a crime, I freely admit that I'm often a grumpy old asshole about this sort of thing when I shouldn't be, and you're 100% correct that people shouldn't be shamed over it.

At the same time, the reverse is also true. Not every plea for punctuation and grammar is creative or ideological tyranny, and if some people react poorly to a text that omits punctuation, that's not something the author has a say in either.

At any rate, I hope this comes of as intended, a genuine, if overly lengthy explanation from someone who supports the widespread use of punctuation, and not just Grandpa Simpson yelling at a cloud. =)