Only they aren’t: they’re critical.
The word “skeptical” functions as a subject complement in this clause. The particular complement here is a predicate adjective: the adjective “skeptical” describes an attribute of the subject “critics.” But hidden beneath that grammatical nicety is an utter falsehood.
According to the Oxford English Dictionary, a “critic” is “one who pronounces judgment on any thing or person; esp. one who passes severe or unfavorable judgment; a censurer, fault-finder, caviller.” Someone who is “skeptical,” however, is “inclined or imbued with [an] attitude of doubt or incredulity as to the truth of some assertion or supposed fact.” Because a critic has already pronounced a severe or unfavorable judgment, he can no longer be considered an honest skeptic because he has ceased doubting by acting upon truths not in evidence.
Dishonest skeptics, then, would be those who act upon their doubts because there exists no fact powerful enough to compel them to shuck their skeptical posturing. They are critics for whom skepticism is a convenient prop employed in the service of their criticism; and because they only doubt those truths uttered by those they criticize, their skepticism is not dispositive but tactical. They are not “disposed” to doubt so much as they doubt all statements of a political nature made by those they oppose irrespective of the truth or falsity of their claims. So:
“Critics are skeptical of the President’s claim that it is raining.”
That won’t be heard because the content of the statement is apolitcal, so dishonest skeptics will accept it on its face. However:
“Critics are skeptical of the President’s claim that it has rained more this year than last.”
This statement will compel dishonest skeptics to disbelieve its content, not because it is true or false, but because it could be implicated in a larger political discussion about global warming or the progress of stimulus-aided improvement to the capital grounds. However, had that second statement been made by someone who is himself a dishonest skeptic, his fellows in skeptical dishonesty would concur because, even if it were implicated in a larger political discussion, it would be speaking on behalf of their agenda.
These dishonest skeptics are not skeptical: they are unabashedly and unashamedly critical. By predicating an attribute to them that they do not actually possess, news organizations mask ideological rigidity behind a scrim of cautious deliberation.
All of which is only to say that if I don’t stop watching the news in the morning, these papers will never be graded, that cover letter will never be written, this writing sample will never be revised . . .