Why is more not being done to pressure and/or help these countries deal with whatever their problems are?
For someone that clearly knows absolutely nothing about Central America, Mexico or American interventionism in that region in particular (and many others generally) I suggest a great deal of reading.
I've spent many decades outraged at what the US has done to the people of El Salvador, Nicaragua, Mexico, Guatemala, Honduras and others. I've been there, I have friends from there. It's not about pressuring them to do better. It's been a systematic campaign of war, interference, murder, torture, rape and the support of dictators and utter murderous scum.
Start with Iran-Contra and go from there. The people of these countries have been trying very hard to better their lives where they are. Constant interference by various American leaders, the worst of which I would argue was George Bush senior including his disastrous reign at the CIA, supporting right-wing dictatorships in the region, have left the region poor, demoralised and dependent.
America made it's own bed. And to let children suffer and die and the choice is to do it in Nicaragua or the US, it's repulsive. These countries are owed.
If you have a very strong stomach, Google Operation Condor.