[forgotpwd16]

Actually arXiv is moderated and if policies are violated they may even withdraw* a paper themselves, if it wasn't declined to be published in first place. Regarding policies, it's mentioned that a "submission may be declined if the moderators determine it lacks originality, novelty, significance, and/or contains falsified, plagiarized content or serious misrepresentations of data, affiliation, or content."

*Note that this creates a new version lacking any download which also becomes the default but any previous ones are still available.

[hooloovoo_zoo]

Suppose that arXiv withdraws it and says the reason is fraud. What if it turns out to not be fraud? Either way, what if the author sues for libel? Why should arXiv spend resources evaluating papers after they've already been published on the arXiv? It's just inviting all the issues stackoverflow and the youtube copyright strike system have.

[charlieyu1]

Arxiv does reject low quality papers. Otherwise you will see 50 self proclaimed proof of Goldbach conjecture there. Those rejected by Arxiv usually end up at Vixra

[umanwizard]

Okay then don’t say it’s fraud, say it’s credibly alleged to be fraud.