On the matter of free speech, Spotify isn't a public square. Facebook isn't a public square. A masonic fraternity isn't a public square. One of the key things about public squares is that it's funded by public money and administered by public officials.
How are people so keen on asking private companies to behave like public institutions... without asking for the other critically healthy pillars of public funding and public administration? It's sad, but I think it's because in some ways, people have come to actually TRUST big corps to be more morally responsive and deliberative than their own government. As in, would you rather Facebook own your messages, or would you like to see what concept of digital town square the UK or the US government would produce?