Ask them what Jesus would think about Disfellowshiping and subsquent shunning.
Ask them what Jesus would think about denying children adequate health care.
Ask them what Jesus would think about how he was crucified allegedly on a pole rather than a cross, and why that is more important than the message of the crucificition.
Ask them what Jesus would think about child predators in the cult.
Ask them what Jesus would think about Theocratic Warfare aka. lying to justify themselves.
Anything else?