Apparently Hull City have not lost a Mark Clattenburg officiated game since 2003 (including games against Chelsea).
I agree with you that if it was a player there'd be a massive uproar - because it's cool to think all footballers are thick, racist ****s - but really there is no case against Clattenberg at all and it's ridiculous that it ever got this far.
How do you know he got away with anything? They said that their microphones are on all the time. So all the refs would have had to hear it if he said anything. When the FA announced that the microphones were linked to multiple people clearly they knew nothing was said.
They declined to share their evidence until their own investigation was complete, it was on SSN. As the police were not actually charging anyone the FA were well within their right to do so. They knew there was nothing for the police to charge anyone with so wasting time sharing evidence would just be an inconvenience.
As far as I'm aware, the only complaint to the police was made by that dipshit Peter Herbert and as nobody directly involved filed a complaint, the police didn't investigate anything. The FA can't have declined to give any evidence, if none was ever requested.