> However even when something infringes copyright that doesn’t mean anything necessarily happens. Just look at YouTube’s early history or the mountains of fan fiction out there.
This part is talking about uploading a copy of something verbatim, the way I read it.
That's for content that's reproduced in part or fully, but verbatim (like a song, movie clip, etc, where Content ID can apply).
But the parent's point is you can have trouble even for content where you "retell" something "in your own words".