And it will certainly be in trouble people decided to use it to post an entire Harry Potter novel and it becomes the go-to place to read it.
But Hacker News has moderators, and in practice, these posts are aren't likely to stay long, therefore fulfilling Article 13 obligations.
I'm pretty sure that movie quotes are not copyright-protected. And the last point in the article seems to be there to protects such uses explicitly.
As for the potential for abuse, I don't know, I am not a lawyer. But as I said before, it is just a directive, not a law, and it is incomplete. The spirit is all we have now, there is still a lot of work to be done on the letter.