Rousseau believes dictatorship is bad for the whole society and that it takes away people's freedom to make their own decisions.
That primitive condition can then subsist no longer; and the human race would perish unless it changed its manner existence.
This is the fundamental problem of which the social contract provides the solution.
Fidel Castro was a Cuban dictator who banned free speech, free press, and freedom of assembly. Rousseau would have disagreed with Castro's way of thinking and would have told Castro about the downside of dictatorship and its effects on the society.
A society under the influence of Rousseau would be a society in which the general will is always right. Whoever refuses to obey it shall be compelled to do so by the whole body