Yes but they won’t count for ranked

Fun fact: a block feature is required to be accepted by the Apple AppStore review process. So Twitter will disappear from Apple devices with this change.

Since this got some votes and became visible, here’s the source:

Apps with user-generated content present particular challenges, ranging from intellectual property infringement to anonymous bullying. To prevent abuse, apps with user-generated content or social networking services must include:

- A method for filtering objectionable material from being posted to the app

- A mechanism to report offensive content and timely responses to concerns

- The ability to block abusive users from the service

- Published contact information so users can easily reach you

https://developer.apple.com/app-store/review/guidelines/#user-generated-content