It is Annoying that – if we assume for the moment that an organisation's main/only purpose for posting on social media is to tell people about its events/initiatives – it is now entirely unclear where to post them.
There are contending ethical imperatives and other kinds of claims for each platform, but what is lacking is any kind of clear picture of "I post it in this place and people will see it".
(Mastodon is where I do my personal posting, as you can see, but it lacks "audience" numbers.)