They probably never saw the stuff you wanted them to sign. I had the pleasure one weekend in Sonoma to meet a lesser known NASCAR driver that is now a member of the media. He was hanging out in the park with his then crew chief so I struck up a conversation with him. He was really cool and down to earth. Anyway, I asked him what he hated most about being a "celebrity" and his response was signing autographs. He explained to me that walking down the street signing is one thing because you see the person face to face, take what they want signed, sign it and return it to that person. He enjoyed doing that because he was able to have interaction with the person requesting the autograph. What he hated was when he got back to the shop they would have all sorts of posters, die cast cars, cards, pictures, etc. just lined up all over the place and he would spend hours on hours in a room just walking down the line signing things. That's what he didn't like. He also said (and what may actually apply to your case) that most of the time people would send things to him and he would never get it. His manager, PR person, etc. gets those things first and THEY, not him, determines if it is "important" enough to pass on to him. He said that on a few occasions fans would come up and give him grief because he didn't sign something they sent him. My views on autographs changed somewhat with that conversation.
Anyway, sorry for the long post here. Douche or not he is still the best to play the game hands down. I just hope there is a reason why he didn't sign them.