Most likely, an "activist" has obtained the TRO and found that it does not lawfully provide such restrictions as are sought to be enforced by the council revenue machine.
Quite how someone "validates" a TRO would seem to depend on what meaning you are attempting to ascribe to the nebulous term "validate".
About 15-18 years ago my locl authority TROs had parking restrictions in streets that didn't exist. After intervention by "an activist" (me) and internet research (ppp) it was found that a number of roads in New Romney with parking restictions weren't actually on the TRO. Well, not for New Romney. they were included in the TRO for Lydd, some five miles distant. Somebody had perpetuated the mistake by cutting and pasting and posting in the wrong town. It saved me quite a bit in parking fines. Nobody had bothered proof reading anything.
OP, is the council asking people to believe that none of these PCNs was challenged and/or that none of these questioned the applicable TRO and that somehow whatever errors were discovered escaped the attention of an army of council officers who penned rejections and assembled evidence for tribunals and/or that whatever errors were present escaped dozens of adjudicators over the years?
IMO, as Big X said in the film The Great Escape..DIG!