You're very close to hitting the main point that people miss: Posting on the internet is a global audience and that means writing with a global audience in mind.
It's a thousand times more taxing than a local audience because you lose all colloquialisms and points of common reference. It's more taxing than even writing for a newspaper because even in the worst case of national coverage, it's rare that an article author would have to consider the global perspective (though still required for certain types of news).
This whole article is just the author chafing at WANTING to use social media like ne has a local audience, while being FORCED to use social media with a global audience in mind. I very much empathize, in the same way I empathize with product manual writers or software documentation authors. Having to come up with every way some dickhead is going to misunderstand you is a massive undertaking. And THEN you have to come up with all the ways that some dickhead will TRY to misunderstand you. To guard against all of them is impossible, so you just have to shore up as many sides as you can and take the criticism as it comes. That is what it means to write for a global audience, and its exhausting.
So I don't blame anyone at all for saying "this isn't my job, fuck this."
Personally, I just write how I want to write and let the chips fall where they may. I don't begrudge anyone for just not writing at all, and leaving all the chips alone. But I also don't find their intention to do so particularly worth description; especially not in long form. It's not like its a binary choice. When you have the spoons to troll any troll that comes at you, and engage earnestly with anyone who is trying to engage with you - no matter how misguided - then have at it! Make your posts and enjoy or muddle through as applies. And on days when you don't want to deal with it? Just shut the fuck up. Don't say anything. Don't reply to people. Don't engage at all.
It's that "easy".