Did not such intervention help the nations as creating a stable economy helps all the people, and the U.S. did not go to war? Is it better to let a neighbor go bankrupt and starve than to intervene when one has the means?
Most US interventions in Central America were not undertaken to benefit the economies of the countries in question, but to protect US businesses and investments there. In Nicaragua, for instance, the US government supported the overthrow of Jose Santos Zelaya in 1912, and then sent in Marines to support his successor. Zelaya had attempted to implement a tax on US-owned sugar and banana plantations in Nicaragua, and executed a handful of Americans who participated in a rebellion against his rule. Similar episodes took place in Honduras, Cuba, Panama, and other Caribbean and Central American nations, with the US military intervening on behalf of US-owned industries.
"Intervene" is a bit of a cover word. Does it mean giving them aid? Invading? toppling their governments? Because the US has resources, does that require them to come to the rescue?
If the US, or any country truly wants to help another, the best, only and most effective activity would be to trade. Mexico, for example, has a supply of oil; the US has a huge demand. By trading, wouldn't that be benfitting the people of Mexico and the US?
Trade can only function where there is political stability, and stability can only be achieved when there's minimal corruption in the government and maximal freedom for individuals to pursue their various business interests.
Are the problems in Central America from their own internal difficulties, or undue (and unjust) political influences from the US?
I think if we look at history the various US interventions in Central American countries have not worked out well, unfortunately, and in countries such as Nicaragua US support for various regimes has actually helped to prolong civil wars and destabilise the country as a whole in the long term.
Did our interventions truly help their economies? I mean, two of the places we intervened early in the century were Nicaragua and Haiti. Neither of those countries ever seemed to have what you would call a stable economy. Later, it's not like Guatemala thrived after we got rid of Arbenz. So I'm not really sure that we stabilized anyone by intervening.
It would help greatly if you could tell us which historical period you have in mind, which specific countries (if any) you are thinking of, and what sorts of intervention you mean. If you supply these kinds of details, you are more likely to get helpful responses.