Before someone tries to explain the 1st amendment to me, don't bother. I understand it very well.
Twitter is not the government, and therefor is not bound by the 1st amendment. However, they enjoy Section 230 protections (in that they claim to be a "platform" and are not liable for the statements of their users), while at the same time behaving like a publisher (exercising editorial control).
Publishers DO NOT enjoy Section 230 protections. Publishers can be held liable for the speech of their authors.
Twitter exercises this dual classification in surprising ways. While censoring some groups for perceived violations of their policy (namely conservatives expressing opinions), they allow other organizations to flagrantly violate those policies with no penalty (for example, terrorist organizations like Hamas).
If Twitter is a platform, they should not have editorial control over any speech that does not violate the law.
If Twitter is a publisher, they should be held liable for the content posted by terrorist organizations, and defamatory content posted by users (authors).