After one has turned on bullets in LibreOffice it seems impossible to ever get rid of the indentation after deletion the bullet with ← because only the bullet disappears, but not the indentation. The help page claims that this can be fixed in the Bullets menu, but it can’t because there’s no option to turn off bullets.
I can see how a separate webpage documentation can get out-of-date quickly because any documentation that isn’t generated from code directly doesn’t make sense.
Why not make the last removal operation remove the indentation? Please make sure that such obvious design drawbacks don’t make it into releases - I’d report them, but Libreoffice bug reports are ignored for years or at all afaik.
Did you try to click again on the “bullet/numbering” button? Numbering and bullet buttons on the toolbar toggles between on and off.