It's the same arguments from the *******s everytime something like this happens: (a) if an ump doesn't enforce a clear rule, then there must not be a rule and therefore Rafa did not violate a rule. Or (b) everybody violates these rules, so it is unfair to gang up on Rafa when he does it.
It's always some tortured piece of logic constructed solely for the ad hoc purpose of defending Nadal. In order to see this clearly, just ask yourself, if somebody murders a stranger and tosses the stranger's body in the lake, but is never caught, does that mean that the murder was legal? What if the police department knows about it and chooses not to prosecute because the murderer is a powerful pillar of the community? Does it mean that the murder was legal then?
The logic is obviously laughable.
What is just as laughable is your example...
Murder is obvously a crime and in itself morally wrong. That's why there is no debate about whether a murderer needs to be punished.
The same isn't logic doesn't work for tennis rules. Taking 30s to serve is not in itself a morally despicable act. It is just wrong because by some rather arbitrary circumstances there just happens to be a rule that says you have to take no more than 20s. This is not necessarily a good rule, just because it exists. This rule was established to benefit tennis and it may or may not do this.
However, it is legit to question such rules whether they still make sense or not.
In case of many sports rules, there is obvously no need ot question them because it all works just fine. But in this case, there is enough evidence to suggest that is is more than time to call it into question. The officials seems to know this themselves, otherwise they wouldn't handle it the way they do.
It was to officials who decided to slow down the court and make tennis more physical in addition to the natural development of the sport due to poly strings etc..
Then it is the job of these officials to check whether their rules are still good under the new circumstances. They make the rules so they have a responsibility towards the players. Yet, they haven't done much to fulfill this responsibility.
Simply saying you guys have to be able to play for hours and obey that rule whether it harms the quality of the game or your health or whatever would be stupid.
I don't say it is good the way it is right now (rule constantly being broken and some random warnings). I think there just needs to be a debate about how it should be. Then we would have a good rule and it would be right to strictly enforce it.
edit: Let me therefore give you an more appropriate example: In the past there have also been laws saying that slavery is alright, women aren't allowed to vote and homosexuality needs to be punished. Now were these rules good, just because a long time ago someone though so? And wasn't many people ignoring them and protesting against them with valid arguments good evidence that is was time to overthink those laws? Or should we rather all be sheep just doing what someone says is right never calling it into question?