Very few instances have full text search enabled at the moment, usually using a special version of Mastodon. Iirc it will be coming to standard Mastodon (as an option) in the future.
A possible explanation for this severe enforcement of the law is that it could be related to other law violations, such as drug dealing.
(See comments on the NextInpact article (in French).)
It’s hidden in the post’s context menu. ;-)
(It should probably be in a comment’s context menu as well.)