That little hard point that you are adding by itself is not the problem, it is the extra stresses that are added to the fork by whatever mass you add to that hard point.
The fork in the photo that is hard to see because most of it is behind a pannier is a carbon fork that is extra strong because it has the extra strength built in for the rack and panniers. And if he crashes, the stress from the impact to the rack and rack mounts on the fork.
A friend of mine got that fork so that he could add panniers to his touring bike.
