Content Warnings (CWs) in Mastodon hide the main part of a message underneath a title. If people want to see the main message, they click next to the title to open it.
This is used by the post author to hide anything they think other people might not want to see by accident, for example something offensive, potential spoilers or really awful puns.
If a thread contains lots of CWed messages, you can open them all at once by clicking on the 👁️ icon in the top right corner. Clicking on the 👁️ repeatedly toggles the thread's messages open and closed.
Alternatively, you can make all CWs open to you by default by going to Preferences > Appearance > Always expand posts marked with content warnings, then click "Save Changes".
An oddity in English: "island" and "isle" are unrelated. "Isle" is from Latin (insula), and came into English as "ile" through French. "Island" is Germanic, and was originally "iland". In the 16th century, scholars added the "s" back into "ile" to make it conform more with the Latin original - and people mistakenly started adding it to "iland" as well, creating the modern "island".
Facebook's leaks revealed it views 11 and 12 year olds as an untapped market. Even knowing it was harming them. Analogies to Big Tobacco are not out of line here.
Maybe the most revolting part to me is how they use family ties to push their destructive product, encouraging promoting play-date scheduling as a way to encourage getting kids locked into Facebook.