The biggest difference is not just origin, but religion. Despite the parallels in the behavior of the French and the cannibalistic acts of the foreign party, the French believe themselves exempt from criticism due to their civility. Their violence is justified, according to their religious fanaticism. This is exactly what cannibals believe about their own practices. Similarly, Irish upper-class society, when Swift wrote his piece, considered the peasantry to be undignified and inferior, most likely due to their religion.