The police fucked up the evidence , they and the CPS overreached hugely but the main problem is the law itself.
If you have a law intended to criminalize sending thousands of letters and menacing emails a week but written so loosely and with such a low bar that everyone with Internet access breaks it almost daily, are left in position where is ideological decision who to prosecute or not.
Previous colleague regularly said she needed "get a waggle on" (not wriggle) in emails and wrote that she had "visualised " instead of "seen" into formal client notes. That caused me endless annoyance and anxiety for years.
That section on malicious communications needs scrapping, have been so many cases where used wrongly in my opinion.