The CEO is not the authority on whether the MRP got it right or wrong though. He is just offering an opinion, a wrong opinion in this case.
And yes, it is a valid argument. Either a reckless tackle will be punished with a sin binning or it won't. It can't be a discretionary thing otherwise what is the point of having a lineation between careless, reckless and intentional.
So, per the NRL laws:
PLAYER MISCONDUCT
A player is guilty of misconduct if he:
2. ‘When affecting or attempting to affect a tackle makes contact with the head or neck of an opponent intentionally,
recklessly or carelessly’
Sin Bin
The six main reasons for a player to be temporarily suspended for ten minutes are:
6. Foul Play*
* Foul Play – A player will be sin binned for foul play in circumstances where, in the opinion of the Referee, the foul play does not warrant sending off, but is serious enough to place the player on report, and the player injured from the foul play is unlikely to take any further part in the game.
You're upset because they got it right.