Why didn't Mr Weasley bring Hermione and Harry safety (QWC)

So there are a bunch of rogue and highly dangerous Death Eaters (or/and wannabe-DE) at the quidditch world cup, torturing muggles. I understand Bill, Charlie and Percy helping the ministry.

What I don't get: Why does Mr Weasley decide to help the ministry instead of bringing Hermione (Muggle-born and in sooo much danger there) and Harry Potter (!!!) to safety? Okay it's in later books that we learn this but Mr Weasley could have apparated with Hermione and Harry, even a few miles away from the campsite should have helped.

A good father figure, a good guardian, would have gone for protection of Hermione and Harry first, I think.