I am not sure why they thought that this would generate support for gun control. Why did they think that the gun dealers who were a part of this program would stay quiet if they tried to destroy the industry? Why would they think that semiautomatic weapons would be popular in Mexico, a countyry awash in automatic weapons?
I'd like to remind you that Time magazine ran an issue in the 1980s that was devoted to pull on the heartstrings of naive and unsuspecting Americans to try to outlaw private gun ownership in the US. They shamelessly stated in letters to former subscribers that gun control was too important an issue to bother with little things like "the truth." There's no reason to believe that Time nor any other news provider would bother with any reports other than how terrible the unending flood of guns from US civilian gun stores to the drug cartels and criminal gangs in Mexico, Central and South America. The phrase "if it bleeds, it leads" would be operative to a level never before seen.
Mark