The algorithm doesn't look for self written or AI but name + how many times has been posted.
Steem Curators search themselves for posts and comments to upvote. They should search the entire platform l, not just visit communities. It is hard.
Moderators, Steem Curator should figure out if it plagiarism, AI at work, now those they vote for and they could know way more if the invested the time.

The newcomers have their own SC team. Are they all upvoted? If I stop by I rarely see upvotes let alone tips how to improve.