I agree for the web im general, but I don't think it applies in this case, because he was free to say whatever he wanted, but when he agreed on the deal he also agreed to represent Spotify, and therefore all its employees. It's like a sponsorship.
That's within their right of free speech, and Joe Rogan has equal free speech rights to make counter-demands. You believe in free speech don't you?
It should be noted that union organizing activities are protected in the US from employer retaliation.
I'm saying their ideology is unacceptable (anyone calling for censorship should be shunned), not the fact they're speaking their mind.