My take is simple, I love Mo, I respect what he has done for this club and he is a legend.
Legends are still held to a standard of behaviour, that goes for him, Klopp and anyone associated with the club. That open disrespectful behaviour was not ok, after Klopp cooled it with the post match interview, he again was still kicking off when he walked past... he is being petulant, this is not ok.
The manager is the boss of the team, he has tough calls to make but I always say the best way to answer the manager if he drops you, or tells you to go prove yourself no matter how many goals you've scored, you go out there and put in a performance to make him regret dropping you, or whatever.
This is very poor from Mo and he deserves to be disciplined for it. Really disappointing. Don't like players thinking they are bigger than the manager or too big/legend status to get away with this behaviour.