The underlying issue is that this was a case of force majeure. There was no plan in place for this set of circumstances because this set of circumstances had never been encountered before. In retrospect, it was obvious that they could have planned around it, but as the commentators frequently alluded to, nobody anticipated any rain yesterday morning, much less the deluge that inundated the circuit.
Admittedly, the cynic in me wonders if the furore over the start time was a strategic play; if they foresaw more rain - and the radar showed it - and anticipated lengthy safety cars, then it stands to reason that they would have known about the fuel drop issue, since they would have crunched the numbers. With that in mind, they could have concocted a strategy that deliberately ignored the fuel drop and then argued that the shortened race distance would have meant that they never would have burned off enough fuel. That might sound far-fetched, but it's the kind of loophole that's ripe for exploitation.