There is nothing wrong with "buy this buy this!", that is the legitimate basis of healthy capitalism, and not why corporations are dangerous.
When corporations got out of control in the past, we ended up with things like company towns (where you are paid in "company dollars" that are only valid at the company store and the company apartment buildings), and violent oppressions of labor movements and labor strikes.
You know what saved us from those things? the Government.
Both Government and Corporations can be evil when allowed to run out of control, but there is a crucial difference between the two. The government (at least in theory) is controlled directly by the people, whereas the people have almost no control at all over private corporations, except in instances where they were able to use the government as a tool to set limits on the behavior of corporations (OSHA, Minimum wage, EPA, FTC, etc).
Yes, I agree that corporations at their worst are nothing compared to a government at it's worst, but that doesn't mean you should fight the government (not while we still have the right to vote anyway).
You can fight the burglar AND the pit bull at the same time, or you can take control of the pit bull and use it against the burglar, which would you rather do?