> When you use an LLM to author a post, you may think you are generating plausible writing, but you aren’t

There's some toupee fallacy at play here. The author probably reads a lot of LLM assisted content without batting an eye, but only spots the worse of the LLM outputs. There's a big difference between "write a post about _" vs "improve the grammar/style of my post: _". It's a bit like saying that movie CGI really sucks because you can always tell it's fake.