Many people ask, or are unsure of what irony is.
Socratic (dramatic) irony, the original word as defined by Socrates (obviously), refers to any situation in a work of dramatic literature when the interest in the work is drawn through the audience being aware of a key fact that the dramatic (and in this case ironic) subject is not.
I just think that, as someone who seems to be an island in an ocean of people who misuse or misunderstand the word, this is one of my favorite strips ever.