As I've already said I have little sympathy with the offender but if I'm being generous I think it's sometimes quite a fine line between being a troublemaker and being a vociferous, maybe over enthusiastic fan who starts chants, goads the opposition and perhaps goes a little further than most...
So, given he was ejected by stewards, handed to the police, his ID details were given to the club and he has admitted the offence which explicitly goes against both the rules of the ground but also those at the Amex, what do you suggest would have been the appropriate punishment? 2 games? 4...
Presumably if he had thrown the cup onto his knee first and it had deflected into the air then under the current rules the punishment would have been revoked.
On a related point - is there anywhere more slippery in the world than on those steep steps and concourses at Ajax? Saw plenty take nasty tumbles. Beer, rain (on sodden fans) and the closed roof can't have helped but it seemed lethal.