The blockade of a journalist by a public media institution constitutes a violation of the constitutionally protected freedom of the press and information.

The consequence of the blockade is the violation of the journalist’s right of general freedom of information, which is protected by the German Constitution, which guarantees unhindered information from generally accessible sources.
The blockade also results in the violation of the freedom of the press, which also covers journalistic research.
An intervention by the authorities in the fundamental rights of general freedom of information and freedom of the press would only be permissible if a legal basis allowed such an intervention. However, neither German federal nor state law provides such a basis for Twitter blockades.
Therefore, public broadcasters are not allowed to block anyone on Twitter. If they do so, they are acting illegally.