Continuity mistake: When the dad is offering the son some ice cream, the cone he offers is a single scoop. In the next shot, as the son takes it, it is now a double scoop. In addition, the scoops change from single to double and back and forth in the next few shots.
Revealing mistake: When the dad and Charlie are eating their ice cream cones at The Beginning of the episode of the episode you can tell that the ice cream is fake.
Answer: As he stated many times throughout the series, Mulder needed Scully to be sober and skeptical. Whenever Scully's skepticism wavered and she started questioning her own rationality, Mulder would try to restore her sense of skepticism, because he needed her to be clear-thinking.
Charles Austin Miller