I am not sure if all of them are AI generated...
And I'm not saying that all the posts there are exactly written by AI. But there are a lot of those posts. At least that's what the AI checker I used to check the posts says. And yes, I did not check all posts, but only those that made me suspicious.
I checked only the first page. There are a few AI generated text in the first page, while the rest are some randomly generated hooks by the project owners which they shared to a group of people whose duty is to copy and paste the posts in intervals. By suspicion, a newbie could be misinterpreted for using AI because they have written enough posts to enable people master their posting patterns. But most AI users I have seen are newbies. Once the grammar is too corrupt and nicely formatted and posted by a newbie, it could be AI generated (80%) turns out to be true.