Almost every PM I've worked with had an engineering degree and/or previously worked as an engineer. This "Josh" sounds like a strawman or you've had bad luck with PMs in the past.
It also sounds like you have a PM on your team, but they actually have the title of SWE or Eng. Mgr. They probably spend > 50% of their time on the above listed responsibilities rather than engineering. Hopefully they don't get docked in their performance reviews for essentially performing the duties of a PM rather than those of an engineer.
It also sounds like you have a PM on your team, but they actually have the title of SWE or Eng. Mgr. They probably spend > 50% of their time on the above listed responsibilities rather than engineering. Hopefully they don't get docked in their performance reviews for essentially performing the duties of a PM rather than those of an engineer.