It doesn't really matter though, because in California, the state constitution explicitly states that privately owned spaces open to the public (so twitter) must guarantee freedom of expression. The case law is pretty absolute and settled in this regard. Most famously... shopping malls in California have to allow union protests within the malls (with only mild regulation, mainly around safety / opening hours). Thus, by the Supreme Law of the state of California, as a private company, Twitter is legally obligated to -- at least for California residents -- not restrict their legally protected speech. Twitter frequently does this to california residents, thus violating California law. If the law was applied equally, they would be fined and censured as the malls were who tried to union bust.