my 2 gsd does it to.not everyone.
i think it's because dogs does not see all the colors like we(human) do,and they can't make out the faces,so they get nervous.
let me ask this,does it get worst when it's dark?
sometime when they see a white person,at night,they react the same way.
this is kind of weird,because i was going to start a post like this,but i was not sure if it was going to be "touchy"for some.
i was driving with my 2gsd about 2-3 weeks ago,and i was stopped at a light.i was on the right lane.then a black women,about 50-60,was walking on the side walk,coming toward us and when they saw her,they went off! she stopped and looked at me,she was so scared that she went off the sidewalk into the grass a good 20-30 feets.
usually they don't act like this when they are close to afric/americ.
i take them to pet smart a lot,and there are been many occasion when a black person,including kids,stopped and petted my gsd.with no problem.