oh I see what's going on:
- shares and rebugs with content are inherently different
- if you share with no content, the content warning toggle is disabled, because there's no content
- if you start adding content, the content warning toggle will be enabled
- however! you can start writing, add a content warning, and delete the content, resulting in a rebug whose only content is a content warning
EDIT: never mind, if you try to post the rebug with a content but no content warning, it automatically discards the content warning with no warning and posts as a share
