There is a clear possibility that Ferrari has violated the rules in order to obtain a competitive advantage, most likely by finding a way around the fuel flow meter. Anyone who denies this possibility is delusional.
"Oh but maybe it was legal and the FIA just didn't want to disclose the technology"
If that was the case, the FIA's statement would have said something along the lines of "The system was found to be in compliance with the regulations, but further details won't be disclosed", nowhere in the statement does it say it was legal, and legal technlogies don't require settlements and teams doing community service.
"Then why didn't they punish Ferrari by removing points or excluding them from the championship?"
Simple, because any time something doesn't go Ferrari's way they act like a child throwing the toys out of the pram, and the FIA doesn't want to run the risk of Ferrari withdrawing from F1 (which I find absurd, Ferrari needs F1 as much as F1 needs Ferrari, and no competitor should become bigger than a whole sport).
"Oh but Mercedes has DAS"
You mean the system that they asked FIA about before implementing? Or you mean the system the FIA has publicly said was legal for this season? And even if it was illegal, two wrongs don't make a right.
I believe I have condensed 95% of the arguments from this thread so far on this single post.