That phenomenon is called "Coolidge Effect" and applies to many male vertebrates, as chickens, rats and, in a certain way, humans for example.
I wonder where this aggressive behaviour comes from as long as the drake was not imprinted on humans because in that case it is very clear where what is responsible. Is it genetics? Are there aggressive bloodlines or is it just a behaviour that pops up randomly?
My drakes behave fine. My oldest drake is very tame and when I herd him into the shed at night I need to give him a little push now and then because he doesn't want to move, but he never attacks me. When he sees me he sometimes walks towards me and starts headbobbing, but I don't know whether he is just excited because I may bring food or whether he is greeting me.
His two sons try to rip off my fingers when I feed them treats, but that is no aggression at all. They actually get a little afraid of me when they think that I am after them.