Let's put it this way.
Think of it as a loyalty thing.
Imagine a Wise old white-haired Chinese emperor presiding over the Kingdom.
Suddenly some rascally rebel comes in and calls him a $h!t-head out of nowhere.
Wonderful - so I assume that for starters the 'rebel' has very good reason to believe that emperor exists. I assume also that the rebel has good objective reason to believe there is a law against insulting the emperor and what the penalty would be. Also note there is very good reason that a rebel in a place the size of china might potentially have cause to be disgruntled at the emperor despite the emperor's best intentions; because that is how empires work, they involve large organisations and numerous layers of hierarchy, the often inequitable flow of goods and service, the fallible formulation and implementation of justice systems etc. I would also note that there is nothing objective which would imply that it is more wrong to insulting the emperor as opposed to any other person - only that the emperor decided it was more wrong and that this is backed up by force.
The protocol requires that these people are put to death for the sake of the stability of the kingdom and the recognizing of the status of the leader. Regardless of any feelings involved, whether they matter or not, it is for the sake of preventing dishonor and discord upon the status quo, and rightfully so.
And here is where your analaogy fails even further - see in a kingdom, the 'protocol' is the result of the king's own (and previous king's and religions) rulings and traditions - contrast that with the case for some divine kingdom, does 'god' inheret protocol from another series of prior gods or some other unalterable source? For what reason would god not have control over this 'protocol' moreover how could god's 'kingdom' become unstable (and what would that even mean in a divine context)?
It is claim that relies on innumerable layers of assumption without basis and directly contradicts with associated claims about that very same god usually by those same believers (such as love, mercy etc). It is not an internally consistent proposal.