It's also reasonably effective proxy to determine whether somebody is actually passionate about the topic they're writing about. If you've got a very strong interest in a specific niche you're typically able to pour pages and pages of ink down talking about it. If you can't be bothered to take the necessary time to distill your thoughts, it signals to me that your thoughts on the topic aren't as worthwhile as someone who's deeply invested in it.

Of course this proxy isn't perfect, I understand many people use AI to make their writing more comprehensible when English isn't their first language.

Often the commentor wants to take a shortcut and just say it's AI written and hand wave it away.

A comment should argue the merit of the work not attack the source or medium.