Re: Did we ever see anyone vote in the Federation?
While the Federation Council may be a democratic body I would imagine that not all of the member planets are what we would call democracies. Ardana in The Cloud Minders was a Federation member but the Troglytes certanly were not casting votes either on their planet or in the Federation Council. In Amok Time T'Pau asks T'Pring if she is willing to become the property of the victor. Perhaps married Vulcan women don't vote either, letting their husband deal with such matters. The Federation would be pretty boring if all the planets looked like mid 20th century American their politics.
And it would be morally disgusting if it did not protect the inalienable right of all of its people to participate in the democratic process and to be equal citizens before the law.
"Every line of serious work that I have written since 1936 has been written, directly or indirectly, against totalitarianism and for democratic Socialism, as I understand it." - George Orwell, 1946