Did Horus even really care why The Emperor left The Great Crusade?

As far as I've read, Corvus is the first Primarch to just directly ask The Emperor why he left The Great Crusade and the Emperor tells him. If Horus just asked prior to the Heresy events, do you think he would have gotten a answer? Do you think he even cared about the answer or was more bothered by the need to ask?