Getting it backwards

Washington Post reporter Ed O'Keefe, responding to a reader who asked "what's so complicated about abandoning the 'don't ask, don't tell' practice." 

Ed O'Keefe: It requires a mix of executive and legislative action, and President Obama has said he wants to end it, but wants to make sure the government does so properly. That means a mix of executive actions that he can take and Congressional legislation that will make it law -- meaning his predecessors can't enter office and reverse his executive decisions. 

It also requires a culture shift at the Pentagon, where many current and former officials support DADT's repeal, but others still oppose the idea.

No.  A "culture shift at the Pentagon" is not necessary in order to end Don't Ask, Don't Tell.  A culture shift at the Pentagon may be necessary as a result of ending DADT, but it is not a necessary condition for ending the policy.

The military follows the law, it does not set the law.  O'Keefe's answer suggests the opposite: that civilian leaders cannot enact policy until members of the military agree. That's antithetical to the concept of civilian control over the military.