[forgotpwd16]

Most academic nutjobs tend to build a world of their own with gibberish papers. This dude instead decided to take others' work and has even gotten an identity theft charge on him.

For your question, fraudulent copyright infringement claims are plaguing most services hosting content (GitHub, YouTube, etc). Haven't seen it again on ArXiv so chances are it's a rare occurrence. So the admins probably weren't sure what to do. At least in the comments, they make it clear, it wasn't due to policy (as mentioned in the stolen paper) that yours was removed but essentially due to being forced by the claims.

What surprised me was that a journal in MDPI garbage land, published an expression of concern.