My only experience in the field is working for an "old school" publisher, where copyright concerns like the one described in the blog post would be the responsibility of the acquisitions editor (an employee of the publisher). Our printers were a separate company, who, like you say, had no editorial responsibilities. "Old school" publishers do typically coordinate distribution, though. There are also some that support print-on-demand (for example, Manning).

I think it's instructive here that KDP stands for Kindle Direct Publishing, not Kindle Direct Printing.