Social media is supposed to be the digital commons. Without a dislike button, then the media cannot be a commons. You go to the town square and start spouting offensive bullshit you’re going to get the proverbial rotten tomatoes thrown at you, mockery, and getting shunned.
With only having a like button, Twitter amplifies the message of bad actors and encourages rage responses. That’s the point though isn’t it? Engagement metrics to sell rage at a discount instead of the whole normal population buying a post with dislikes and moving on.