One can only wonder what kind of “deal” Gen. Dempsey had to make to get such an offer.
You can be sure that any officer promoted to the rank of Lieutenant General/Vice Admiral and above will be required to promise to support the repeal of DADT and required to support the Administration’s defense policy. That has been true for all administrations. Any dissent will have to be done privately. MacArthur publicly disagreed with Truman. He was fired.