Free speech does not mean a company has to take part in spreading it :). Free speech is about your right to speak without the government locking you up, or censoring those who choose to broadcast/spread it. But nothing about free speech says someone else has to listen or spread it for you, companies included. The line is drawn at calling for violence though, which is pretty fucking tricky to navigate.
I see you're not a big fan of net neutrality.
This is also the same line of reasoning that has been applied to deny service to gay couples and people of color. You can't discriminate based on ideological or social factors, however ludicrous someone's position may be.