Ok I will play the devils advocate-

Did you call your intentions to the left and right to make sure everyone heard?

Were you loud, could wind or plane noise interfered with your call?

How much time had passed from your call to the pass? Long short etc....

How did this guy fly the wrong direction??

And you said that you collided while exiting the low pass- I take it you were maneuvering in some way not flying rock steady 3' above the runway..

This is not a flame in any way I just don't agree with total blame falling on a nameless individual who is not here to defend himself... I am sorry for the loss I am a big fan of flying wings...