Really don't get why anyone hugely cared that much about this or why they wanted to see it as a referendum on Renzi, other than for its own sake.
Also, I still don't get the M5S. They remain essentially an anti-party, devoid of any unifying and guiding ideas. To an extent all populist movements of all stripes suffer from this, yes, but M5S have been vague and ambiguous even by those standards. Thus everyone just subconsciously reads whatever they want into their slogans.