I think Scoop is sort of joking, but the caption for the clip makes out that he's crazy or something. It's a hypothetical argument. He hasn't lost control of his faculties.
The focus of the clip should be on Bobby Davro thinking that 4.5 lights years equals tens of thousands of years.
If it takes 4.5 light years to travel somewhere in space, then it takes 4.5 years to get there at the speed of light.
Which means to get there and back to Earth would take 9 years.
