As answered by "No One" - in the 1940's the government of Costa Rica realized that "the greatest threat to a democratic government in Latin America is a standing army" - there had been so many military juntas which had overthrown so many democratically elected governments (some with the assistance of the US CIA) - that they abolished their military, and have had a stable democracy ever since.
Because back in 1948 a general called Jose Figueres abolished all the military forces.
My guess is, that is what the citizens of Costa Rica want.
Why not?