I'd like to point out that in a system where California didn't count she wouldn't have won 48% of the popular vote either.
Could you explain what your point is, please?
Derek said "Note that every system I know where people directly elect president it is not a "first past the post" plurality vote. If neither candidate wins a majority, there is a runoff between the top two.", and then commented on how the 48% would not have been enough in some other countries. I provided an example of a real system in which 48% (and more votes than her adversary) would have been enough.
I don't know why you reply in that fashion. I'm not saying the Argentine system is good, by the way. Personally, I think it's bad, even though no worse than the Electoral College system it replaced in 1994 (which was for essentially a copy of the US system). But it was an example of an alternative system where her numbers would have been enough.
Of course, if that had been the system, it's unclear what the outcome would have been. For example, some conservatives in California may well not have voted because they thought Clinton would surely win California anyway. Then again, some progressivists in California may well not have voted because they thought Clinton would surely win California anyway.