I don’t know much about Oscar Wilde besides his writing, but as witty as he was, I get the impression I would not have wanted to sit through a critique from him. He seems fairly fond of the word “stupid,” and it’s not a favorite of mine (to put it very lightly).
I think it would be fairer to say that getting irony is hard – irony is by its very nature not obvious. It requires inferences and practice, and even excellent writers and readers can have trouble telling it from other forms of wit.
Of course, being witty and being fair don’t always go together.