'Cause they're evil

Its the one panel pause that makes the joke work for me...

Lords & Ladies

Elves are wonderful. They provoke wonder.
Elves are marvellous. They cause marvels.
Elves are fantastic. They create fantasies.
Elves are glamorous. They project glamour.
Elves are enchanting. They weave enchantement.
Elves are terrific. They beget terror.