- the organizers are doing what they think is best for the attendees, and what the majority of attendees want
And, you should consider: "what if everyone did that?"
I gather they had a paper they thought was important, but was not accepted to the conference (so they had no formal chance to present it). What would happen if everyone who's paper was rejected could just wander around passing it out and pitching it to random passerby's? I think almost everyone who attends conferences would not want that.
I wonder what other options they considered. Did the conference have a less formal forum, like workshops or something? Could the topic be discussed there? A poster session?