Why is Twitter censoring links to Signal?

Twitter, renamed X by owner Elon Musk, is reportedly blocking links to the messaging service Signal. Matt Binder:

X, formerly Twitter, is blocking users from posting a "Signal.me" link through DM, public post, or even in their profile page. When trying to post a Signal link, users receive a variety of different "message failed" prompts depending on what version of the X platform they use (i.e. X for web, X for iPhone, etc.) … Users who attempt to click on a "Signal.me" link already posted to X are currently met with a warning page from X that reads "Warning: this link may be unsafe. The link you are trying to access has been identified by X or our partners as being potentially spammy or unsafe, in accordance with X's URL Policy." However, users are given the choice to ignore the warning and click an additional link on the warning page to direct to the original "Signal.me" URL.

The context: Signal is a method being widely used by government employees to communicate with one another since Musk's "DOGE" agents were given access to official systems as part of his purge of federal government.

Signal has been an important tool for journalists over the years as really one of the few services that are truly private. All messages are end-to-end encrypted, everything is stored on device, and no content is kept on any Signal servers in the cloud. If a source wants to reach out to a reporter and be sure their communication would be as confidential as possible, Signal is usually one of the primary methods of choice.