Unless of course one follows the reasoning of the media, who say that the American voter has a right to know such things because a man who cannot be loyal to his wife can also not be loyal to his country and his people. The three treaties above, some of the basics of human rights as we define them today, all recognise a limitation to the rights of the individual. Freedom of speech is no exception to this. The rights of each individual are limited by the rights of others. These rights do not merely include freedom of speech, but equally a basic right to dignity, privacy and respect and the basic right not to be subjected to degrading or inhuman treatment.
Human rights serve a purpose.
They have to give citizens a shield, a protection, against their government and their fellow men and enable them to life a free life. This leads to the question if the shield may be used to justify attacks against others. In my opinion, there are limits to freedom of speech just as there are limits to any other basic human right. The first and main one is that of individual responsibility. Individual responsibility, by the way, is also one of the basic principles of Liberalism.