I understood the GP argument as "having voted on the issue", not "having voted to leave". The former implies that a significant portion of the population want independence.
and i'm not sure i understand you correctly, but the very first sentence in the wikipedia link says that the 1995 referendum was the second one... this [1] was the first.
also, refuting one argument does not shoot down unrelated arguments.
https://en.wikipedia.org/wiki/Quebec_referendum,_1995