I've seen this argument so many times. I like something, so we have to make a law to force it to exist. Or, I don't like something, so we have to make a law to make it illegal.
Unless there is a monopoly, and social networks certainly aren't one, there's no reason to force them to do anything.
So why are we forcing social networks to do a lot of things already today: We force them to remove illegal content, remove content that is not suited for minors, moderate content that is traumatic, protect people's privacy etc?
I don't really understand? Is your point that we should not be doing this as well? Is your fear that the state of California will moderate Twitter?
I've seen this argument so many times. I like something, so we have to make a law to force it to exist. Or, I don't like something, so we have to make a law to make it illegal.
Unless there is a monopoly, and social networks certainly aren't one, there's no reason to force them to do anything.