He was probably a hot topic for a while in the Starfleet newsletters after he was discovered about a quarter century earlier. But people likely reacted to him much in the way the EMH on Voyager was treated initially, as some sort of advanced hardware/software, not as an individual.
One of the best clues is in "The Neutral Zone", when L.Q. "Sonny" Clemonds points at Data and asks Riker, "What is that?" Then Data turns around to see what he's pointing at.