I think the main problem with freedom of speech simply the lack of understanding of what it actually is. Freedom of speech is being able to speak your mind without being punished by the government. Twitter for inatance, has nothing to do with it, since Twitter is not a government and users are not its subjects.
Furthermore, freedom of speech is not and never meant to be, without limits. I cannot start a political party with the main political point being, lets kill all blonde people. Or let's ban all gays.
Thirdly (is that a word?) freedom of speech does not mean freedom of consequences. If you walk up to your boss and start calling him an incompetent piece of shite, he can fire you without impeding your right to freedom of speech.
Im sure there are people who advocate unlimited freedom of speech and maybe that would work, if the world wasn't full of cnuts, but eh, sadly it is. So everyone saying anything that crosses their mind hardly seems like a Utopian concept.