I'm not a space geek so I might be missing something but I thought that the Saturn V was still the most powerful ever?
It was a bit confusing the way they phrased it on the show, but I'm pretty sure that they were acknowledging that the Saturn V had a higher payload capacity than the Falcon Heavy, not claiming the opposite. If I recall, they wondered how the two compared, then Steve read the payload capacities for both and then said something like, "so, yeah, bigger" — meaning by that the Saturn V.
I went back to check and here's what I heard:
"With the ability to lift into orbit over 54 metric tons (119,000 lb)--a mass equivalent to a 737 jetliner loaded with passengers, crew, luggage and fuel--Falcon Heavy can lift more than twice the payload of the next closest operational vehicle, the Delta IV Heavy, at one-third the cost."
"One third the cost!"
"One third is sweet but Jay, can you compare this, can you put this in relation to Saturn V payload?"
"Yeah, 119 thousand compared to 90 thousand on the Saturn V. So that's more."
So I'm not sure where the Rogues got that 90K number from since the link that I saw said that the Saturn V is 310K to LEO.