The Clueless Listener.

I looked up the word Critic on Dictionary.com (http://dictionary.reference.com/browse/critic)

I was surprised to find out that being able to do what one is evaluating, is not required.

Simon Cowell is not a good singer, however he is a very good critic.

Robin's ability or inability to sing does not effect her capacity to judge others. This may or may not be true on a playground.

crit·ic (krĭt'ĭk) n.

- One who forms and expresses judgments of the merits, faults, value, or truth of a matter.
- One who specializes especially professionally in the evaluation and appreciation of literary or artistic works: a film critic; a dance critic.
- One who tends to make harsh or carping judgments; a faultfinder.