“Exceptionalism” is a relatively new noun. The ngram graph above shows its usage frequency over the last century. “Exceptionalism” is a great word because it labels an ugly concept. There is even a wiki article on the word.
Humans are social animals which bond in groups to cooperate, compete and survive. We use language and ideas to aid our bonding and often at the expense of others. Exceptionalism is used to foster identity of a group. The rhetoric of exceptionalism can be used to encourage a group to persevere in hard times or to persecute others. But exceptionalism is a two-edged sword — for dominant groups it can be successfully suppressive but if used wrongly by minority groups, it can lead to persecution. Either way, exceptionalism is problematic.
Picture credit: cheering crowd source