I read the entire article, including the dismissal of X, the implied misleading message discussed, and the links at the bottom to the authors missives which have practically every platform except X.
They MAY have an X bias, but I think a much more generous interpretation is simply that they are highlighting which _alternative_ platforms BBC have given up on.
Threads and Mastodon are both _alternative_ choices, with Twitter being the main real-time shortform source. TFA highlights that BBC is giving up on threads, but not on alternatives in general.
Hold on, _not mentioning Twitter in the title_ implies that they're abandoning Twitter? How do you figure that? The title also doesn't mention chairs or toilets, but one assumes the BBC will still be using those.