From https://www.mdpi.com/editors "MDPI is headquartered in Basel, Switzerland. The in-house staff consists of Managing Editors, Assistant Editors, Production Editors, English Editors, Copyeditors, Data Specialists, Software Engineers and Administrative Specialists. Except for most English Editors, all are employed by MDPI and its subsidiaries and work at the MDPI offices. Our collaborating editors on our Editorial Boards are typically employed at academic institutions or corporate research facilities located all over the world.
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Assistant Editors process manuscripts through the peer-review and production procedures..."
As an author, I exchanged multiple emails with employees of PLOS even before it was submitted to peer review (or reached the editor desk) because the automated process of submitting my paper to the system crashed and required intervention. And mine was N=1, and it still broke. It's not "Google-quality engineering", if you know what I mean. So, all this "oh, that's just an automated system" just does not hold water.
Now, my turn to insinuate. Have you ever written a multi-step workflow management software system that coordinates thirty email threads? If yes, how much human involvement from the operators of that multi-step workflow is needed? And if not a whole lot, do you work at a "cool" VC-funded modern firm, or at a company that got started with servers in a datacenter in the 1990s?