Not having a word that is a 'swear' word doesn't mean that they don't use the same emotions.
I insisted that my pre-school sons could not insult their brother unless they used words of at least four syllables.
So 'pig', 'cretin', 'fool', and the like were all verbotten; but my four year old got his tongue around, "Infuriating brachyosaurus!", to rail at his brother.
We're not calling the lady, or you, a liar, we're simply expressing disbelief that they never find some way of vocally expressing common emotions.
"Thunder and Lightning!", "For heaven's sake!", or my own, "Sugarallywater", are all 'technically' swear words, if used in context.
It's the context that's important, iimmc.
M