Hi Tad, not answering for TinaD but wanted to join in discussion
I think his issues were with Boulder rather than with LE generally. I mean, reading his book and PMPT, it reads like traditional law and order cops routinely resigned from the BPD after taking issue with the DA's office or Koby's approach to policing. In PMPT, Schiller describes him as a 'by-the-book' detective which I thought suggested someone who was the opposite of a maverick. Certainly he doesn't seem to have done much without first consulting the BPD's counsel about legality etc.
Wrt his mental health, I think the fact that he had asked for medical leave was subtly manipulated by the DA's office when he resigned so that people would believe there was a psychiatric problem going on. I believe Hunter went so far as to state on TV that ST did suffer from mental health issues and (again, if memory serves), the Shapiro tapes discussed Hunter's suggestion that psychiatric problems ran through the family. IMO, all of this was calculated to make ST look unstable and not credible since the DA was smarting that (in Bill Wise's words), '..they think Thomas is a f......g hero.'
I personally don't believe that ST was anything other than plain old knackered when he resigned.
This is just a musing, but I think heroism and doing something extraordinarily brave are nowadays easily mistaken for instability since they are so rare and run so contrary to our modern reverence for the sovereign self.
Looking forward to Tina D's views, too.