story
It's a complete-free-for-all.
arXiv moderators do not judge the technical content. They don't filter misleading submissions. They don't filter work in need of revision. This is literally described on the arXiv website: https://arxiv.org/help/moderation "What policies guide moderation before public announcement? "
They filter spammers, check for total obvious nutjobs ("My grilled cheese said P=NP"), for crazy formatting, for blatant copyright violations.
Publishing junk on arXiv is trivial if you're not too crazy and know a little bit how to use the right words. You can publish anything.