Many of those tweets contain direct threats of violence. They need to be reported to law enforcement, not flagged for Twitter to deal with. Also, it seems unusual to hold Twitter responsible for their users' speech. UI tweaks may reduce the amount of hatred seen, but they are not going to solve this problem. Lastly, I spent some time perusing other posts on this blog. They are not furthering any discussion, to put it…
Also, why shouldn't services be responsible for users using their service to abuse others?
If you haven't heard of CCP before, you should take some time to read about the amount of abuse she's faced for campaigning on important women's issues over the last year or so. She's not just some random blogger, she's an important figure in the UK due to the campaigning she's done and the abuse she's received through twitter. This belongs on Hacker News exactly because it's about the intersection of Tech and human beings, and the lack of foresight which has allowed some of this abuse to occur.
Startups should be paying attention to stories like this when they look to design services that are safe spaces that everyone can use without being abused or terrorised by other users.