I think the argument is that those alternatives already existed before. Twitter was not being prioritized, it was essentially mirroring the content already available in RSS, mastodon, etc. So effectively, there’s now one less place where the news will be visible.

However, I do agree with the move, but only because Debian being a FOSS initiative should stay away from proprietary platforms and promote FOSS, even if it means effectively “shutting off” a portion of users who don’t wanna leave the twitter bubble.