Clamp on track brake stress question

OK, here's my take on it. As the pads start to grip the rim, the wheel will be rotating forward, pulling the brake forward too. Once they have gripped and slow the bike, you have the whole weight of the bike and you behind the brake, pushing against it. Without the bolt against the fork crown, all this pressure is taken on the forks at two level points allowing it to twist and exert pressure on the forks. The bolt stabilizes the brake and spreads the pressure to a third point. Does that make any more sense?

In the diagram above, the bolt (6) is extended to the crown, so there must be some reason for it and it can't do any harm.

I think you're on the right track but getting some bits backwards. The little bolt isn't about spreading braking load over a 3rd point - as you say the forces are forwards, so it would need to be anchored into the fork crown to do that, like a normal calliper brake...

When you brake the bracket will flex forwards because that's the way the top of the wheel is moving. But tighten the little bolt so it pushes the bracket forwards, and now when you brake the new forces unload the little bolt but don't create additional flex in the bracket. This should reduce brake judder, possibly at the cost of damaging the paint on the crown.