You're assuming all companies are publicly traded which just isn't the case. LLCs have pass-through taxation and are privately owned. In effect, not double-taxation. And if you don't support any corporations that make campaign contributions to the democratic party, well then you must have figured out a way to telepathically connect to the internet as every major corporation in America makes donations to both sides. If I'm a corporation sending out a lobbyists I buy both politicians competing against each other in a senate race, therefore I can't (and don't ) lose.
The Ethanol industry (and corn ethanol to be exact) that you mentioned earlier made major contributions to the Obama campaign. It's also a horribly inefficient means of producing ethanol. The Democratic/Republican mechanism of American politics is two sides to the same coin.
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