The point was that the US loans while heavily discounted were not “free” or pure gestures of good will. The US had specific terms included for it’s own self-interest (as any nation, especially Britain, likely would have done) and to position itself as the world’s dominant economy after the war.
You can choose to view that as good or bad or fair or unfair. Many in the British government including Churchill and Keynes certainly were not happy about what they saw as the US taking advantage with the terms of the loans, but again they did not have much choice.
Subjectively speaking helping to defeat Nazi Germany and collapse the British empire was incredibly based. The rise of the US empire from that, not so much (imo).