Obama's NDAA of 2013 modified two other acts to make it legal for the US Government to directly fund media propaganda in foreign countries, while also removing restrictions from the US Government funding media propaganda domestically to Americans.  This opened up the floodgates for dark money (since so much of the American Governments financial books are hidden for "National Security" reasons) to be used to propagandize American Citizens through media - anything from newspapers, YouTube "influences", to the legacy media such as CNN, ABC, etc. The claim by the OP is that Trump's EO has "undone" these changes, although in reading the EO I have yet to validate where this is the case.