No-one in the history of this manga has ever cared about reaching the Red Line from behind, everything people care about is Laugh Tale. The guys in your panel probably didn't even know Laugh Tale existed. Being Pirate King in this new age is about reaching the last island and finding Roger's treasure.
Laugh tale is at the end of grand line bro thats never been in dispute. You just cant go past Lodestar to reach it without Poneglyphs. Roger literally says this. This isnt that complicated.