I'm glad to see that Twitter is responding to what users want and need, and acknowledging that there's no easy answers here.
Any sort of blocking solution is hard, I think akin to Facebook's "fake news" problem. There's no easy way to determine what news is "fake" or not. But giving people tools that they can use to manage their own space in their own way is an important step forward.
I hope that this will encourage more people to speak out on twitter about injustice and abuse, since it gives them some ability to shield themselves from any backlash.