Basically, if Chevron hadn't stuck it out and stayed, things would have 100x worse.
They basically used the state oil company as their entire budget, and continually used oil sales to buy votes.
Yes, there are bad actors in some corporations. Yes, some corporations do evil things on occasion to save themselves or to be greedy. But Venezuela proves that politicizing corporate actions, and combining corporations and government is the greatest evil we face as everyday people just wanting to live and let live a nice, boring old life.
In terms of relating this to US current events, the Citizens United case blurs this line, and, in my opinion, needs to be reversed or, at least, tamed down.
It's always good to learn lessons from experience of others instead of having to find out painfully for yourself, and as you point out we should not be complacent to think we are fundamentally different and exempt somehow. A good generalization of this seems to be that centralized power in all forms is dangerous because it easily corrupts, has massive force, is an attractive target for lobbying, and does not respond strongly to the needs of the majority.
Capitalism and American imperialism surely? Nope, this is one of the most unambiguous failures of socialism and totalitarianism.