Because it's a very politically bad question to answer.Imo, Waddle gave his honest opinion.
Why does Waddle saying he would rather play with Jones equate to not wanting to play with Tua? They are not mutually exclusive. All Waddle said was , he would rather play with Jones. It was probably a close decision.
Waddle had great stats with both of them, so if they had asked Waddle still in College with Jones and Tua both already in the NFL, most former teammates will never answer that question, whether he does or doesn't really have a favorite.
Either he dislikes Tua, and answered truthfully, or he gave the answer that gets his QB that has still not reached the NFL drafted higher.
You could be right that he prefers Mac over Tua, but he could just as easy either like both of them as QBs, or prefer Tua, but said Mac to get him drafted top 10.