George Bernard Shaw's criticism of The Importance of Being Earnest in 1895 is directed towards Wilde's use of language throughout the play.
Shaw's opinion is that Wilde's play was funny, or "rib tickling", but that the ample use of epigrams and sarcastic language takes away from what he deemed as the "humanity" of the play. In not so many words, Shaw basically is saying that Wilde invests most of the language in his dialogues into making his characters sound too sarcastic or "smart" with each other rather than using dialogue to create true bonds or bring closure to situation.
Shaw is correct in stating that the dialogue lacked humanity and, perhaps, even basic sentiment a a whole. However, one must remember that, from the get go, Wilde is clear in that the play is not to be taken seriously. It is a "trivial comedy for serious people". Therefore, there is an intention from Wilde's part in employing this technique, and there is no intention to make the play more humane or any different than what it is.