Menem and his cohorts (including the young Nestor Kirchner) auctioned off the country's resources for a song. His plan to privatise everything (YPF, Aerolíneas, Utilities, Transport... etc.) created unemployment in the 25% range which led to the worst financial collapse in the country's history. Yet what is he guilty of? Trafficking arms. Like Al Capone being guilty of tax evasion.
On the other hand, saying Menem's administration was better than the current (lousy) one because there was "a sense of optimism" is akin to acclaiming Stalinism for its great propaganda posters. I'm no fan of the current tenants in Olivos, but do let's put things in perspective.