Twitter needs a dislike button. Every social media platform needs a mechanism for explicit negative feedback. Yes, people will use it to downvote ideas they don't like. Yes, it will come with its own challenges. That's how real life works. It doesn't make that speech disappear, it just deprioritizes it.
Given that he already wants to do this, it's better to let humans have input than to pretend as if algorithms know what's best for us.