We do have civilian control of the armed forces. The question of past experience in the service, though, is the same as experience in any other leadership position.
Also, in England's case, the big red flag was his close ties to the defense contracting industry.
What's wrong with PMs who can't program?
More like what's wrong with VPEng who can't program?
Answer: plenty.
Nothing, if their job is to color code spreadsheets; everything if their job is to actually put the content into those spreadsheets.
Because you end up cutting crucial corners because you think you understand whether the two options are equivalent when they are not. Case in point: the topic we're discussing.