DHS secretly prohibited social media search as part of foreigner vetting process that may have identified Islamic terrorist. Does it matter?

Fearing a civil liberties backlash and "bad public relations" for the Obama administration, Homeland Security Secretary Jeh Johnson refused in early 2014 to end a secret U.S. policy that prohibited immigration officials from reviewing the social media messages of all foreign citizens applying for U.S. visas, a former senior department official said. "During that time period immigration officials were not allowed to use or review social media as part of the screening process," John Cohen, a former acting under-secretary at DHS for intelligence and analysis. Cohen is now a national security consultant for ABC News. One current and one former senior counter-terrorism official confirmed Cohen's account about the refusal of DHS to change its policy about the public social media posts of all foreign applicants.
http://abcnews.go.com/US/secret-us-policy-blocks-agents-social-media-visa/story?id=35749325