The meaning of MacDonald‘s quip whooshed over your head. Read it again.
Even if you try to read it as good bad being subjective I don't think there's any fixed lens though which a history book would interpret the winners being the good guys in every conflict.
The bad guys for sure won the Iraq war.
“We have been the good guys in every single war.”
Rather than “ the good guys have won every single war”.
At least in my history books in school growing, my country was framed as the good guys and listed wars we lost.
That's true, but since they frequently lose, that produces a lot of history showing that the good guys lost.