Since we're speculating on possible reasons/motives for the conspiracy, let's revisit an article in the Washington Times
which suggests the CIA was the moving force so that guns would end up in hands of the Sinaloa Cartel. The Sinaloa Cartel has ties to the Mexican military and would help counter-balance the Zeta Cartel which threatens the Mexican political structure.
Of course, there can be more than one "why" behind Fast and Furious
. A secondary motive of providing statistics and numbers to strengthen gun laws would appeal to many within ATF and elements of the Obama administration.