This is just like how Harold Ford, Jr. on The Five always says he "doesn't disagree" with what's been said around the table.
Democrats can't bring themselves to say something positive about President Trump and Republicans. They have to hide behind twisted syntaxes like double negatives to say something.
-PJ
A Double negative prevents Democrats from creating a soundbite that makes them say that they agree with something Trump did. Most people will just hear the word disagree and Will not understand the double negative. In some languages , the double negative does not even mean the positive like it does in English