> It was correct to oppose Hugo Chavez

Only for Venezuelans. It was none of the US business.

> Meanwhile, the US backed Colombia is doing fine

For debatable values of "doing fine".

> The US also maintains near-guaranteed border security for Latin American nations

Not really.

> The US has been a superpower for ~75 years now and has not attempted to use that extreme power imbalance to annex swaths of Latin America.

It hasn't used overt military power (except in limited cases, like their own CIA-backed agents going rogue on them). It has meddled in Latin America democracies to often terrible results. In many cases, it has abetted bloodshed.