Plate files get released all the time.
Judging by your post history, it seems you are fairly new to GH, so welcome, stranger!
He’s talking about the CASE files in his response, not PLATE files. They are bent from ‘plates’ of metal, but to call them ‘plate files’ is confusing.
Plate files (as they are known in the community) refers to something else that can be generated online with at least two well known tools made by the community for the community. If a designer didn’t release them, you could make your own in a matter of minutes, so I can understand why his time might have sounded aggressive if that’s what you thought the discussion was about.
But the CASE files for this project not only took several rounds of prototyping to perfect, but was itself a refinement of a whole previous round of a group buy as well. The time invested by plastikschnittstelle to refine and improve the design is enormous, those kind of files do not get released all the time
Just quickly, on the note about aggression; it might have seemed aggressive at first, but as I understood it, he reacted heavily initially, then laid out the reason for this reaction in an anecdotal story. So the answer is in the response.