I am against democracy, democracy is just a stepping stone to communism. That's what Lenin was saying there.
Contrary to popular belief, Greece was not a democracy. The rules of Greek democracy resulted in a republic.
The people vote in a republic, too.
If the CIA has need of something Amazon can do for them, then the CIA will spend a part of their budget on that effort. Note that would not be the CIA, that would be the NSA. Like Germany's Abwher, the CIA is the public face of American intelligence who's primary responsibility is to take the blame for the other agencies that actually do almost all of the field work. That is the CIA spending their own budget in the way they think is best. If the government attempted to order you to directly give money to Amazon, just because they think they are a good company and like what they do, that would be a violation of the 4th Amendment. They cannot command you into the slavery (indentured servitude) of a corporation or other private citizen. If an agency that receives tax dollars to achieve a goal finds a private entity to be useful in their efforts, they can contract that private company to help them.
Just as, with your flu example, if there were a severe epidemic there is nothing wrong with using emergency funds to pay for flu vaccines. That is government fulfilling their role of protecting the people. But they can't command you to give the company that makes flu vaccines a percentage of your income for the rest of your life. Then that company would literally own a percentage of you, and be entitled to "their cut" of your income. That's a form of slavery, and it's evil.