@realcaseyrollins Corporations have their own free speech rights.
Suppose Alice says something to Bob. Alice's right to free speech does not oblige Bob to repeat that (even if he were directly asked what she said!). In fact, obliging Bob to do so would be a violation of his own free speech rights which protect him from most "compelled speech".
Similarly, Twitter's free speech rights allow them to configure their server so that it doesn't republish certain content submitted by users. That's not limiting free speech; it's a natural consequence of the corporation's own free speech rights.