And it's not about questions getting closed, it's about downvotes.
And from that to saying that the procedure is opaque, I'd say you'll have to provide some sources about that.
He posts questions that are duplicates but are only obvious duplicates if you're have a PhD in quantum statistics. And he attracts downvotes and gets demerits. Most SO users don't have PhDs, therefore most of the the downvotes and demerits must be due to something mystifying.
The procedure is not opaque because:
Well, maybe his questions may be regarded differently by other people, and then it makes sense.
There's a rule on meta.stackoverflow.com that each such complaint must point to an example question. A good rule.