Since Hannity never officially employed Michael Cohen as an attorney (in Hannity's own words, he never paid Cohen or received an invoice for legal services from him) there is nothing for Hannity to disclose.
As much as there is anything to disclose, Hannity has done so. Unlike the incestuous relationships between the liberal media and the Obama's and Clintons that Hannity exposed in the link above. Shephanopoulos as one example, is not a "neutral" reporter, he was Bill Clinton's communications director, and still does the bidding of the Clintons, disguised as an objective journalist.
