You are right that I took it more as a general comment about all hiring across all jobs.  Certainly was my mistake upon re-reading. So I'll make these comments:

EEE - "Honestly, there is no rhyme or reason for the variety of methods used by individual organizations.  Each organization picks its own selection process."

I suspect we might find more consistency across different police departments than you think, and do believe that any real consistency that would not naturally occur would have to be federally implemented.  More power in that direction is simply not a good thing.  It's certainly harder to spend enough time and resources on hiring (or get a good applicant pool) if too many funds are diverted from policing to other initiatives.

EEE - "For years, researchers have tried to persuade organizations to move away from general aptitude tests and use integrity-based selection methods due to the belief that a person can be taught many things but a person's overall integrity remains consistent throughout life."

This is an interesting idea, and maybe the devil is only in the details.  I generally agree with the concept that integrity of of massive importance, especially in policing.  How to implement that, test for it, etc. could be very complex.  I have a friend who joined the Navy right out of high school, in intelligence.  They tested him extensively in that direction so clearly had a process developed.  And they did a very thorough background check, even contacting me and other friends.  I'm in an FBI file somewhere from this interview.  I remember being a little shocked at some questions they asked me given that they required very specific knowledge.  But the interview was respectful and professional.  And it all worked out.