Question

Why would some consider rousseau a "champion of democracy" while others as a precursor to totalitarianism (dictatorship)?

Answer 1

He discussed for democracy, but not for freedom, appealing that anyone who differs with the general will should be involuntary to monitor it. He appears to be supporting something like an "absolute democracy" with complete civil equality, a factual democracy before a republic, and he openly says that political parties would weaken or disintegrate a political system founded on the general will.  A dictatorship crashes with this wholly for the reason that whoever governs the country is not governmentally equal with the rest of the individuals and can create an oppression of an individual or party.  He is disagreeing for a tyranny of the majority.