Hmmmm. First, Dassault is not Airbus. And from the linked article:
1. "Awarding the contract to Boeing after two years of negotiations, the South Korean Defense Ministry said the decision had been based on three considerations: "the influence on national security, the impact on overseas relations and the effect on overseas market access." The agreement calls for Boeing to deliver 40 F-15K planes over a five-year period beginning next year."
2. "Jerry Daniels, the president of Boeing's military aircraft and missile systems division, called the bidding "one of the most honorable and tough evaluations in which we have ever participated."
3. "I am one of the key personnel in the ministry," Cha said. "America did not pressure us."
And as a reminder, this was back in 2002. Back then the Rafale was not yet in production and only several prototypes had been delivered to the French Air Force and Navy. The F-15 by comparison was in production and could begin deliveries the next year. And in the case of the tanker competition, the aircraft already in production (A330MRTT) ALSO edged out the aircraft still in testing (KC-46).
Further, Korea was not the only country reticent to buy an aircraft that was not yet in production, even by its home nation. It took Dassault well over a decade before securing a foreign buyer. That had NOTHING to do with American "arm twisting".