I ride up there sometimes. Generally I agree that it's best if riders ride on the side of the bridge for the direction they're going. On that bridge, though, I haven't been able to find the access for the northbound side, so I just use the southbound side for bothj directions.
It seemed like access to the northbound side got messed up on the Portland end. How do you get there?
But ya, you are being the A-hole. You shouldn't be rude about it. He could be like me and not know where the access point is. He could just be exercising his right to be where he is. Afterall, it's not your bridge.