The argument is that corporations do what they want, often not because we want to buy their stuff, but because:

• we don't have a choice
• they hide what they're doing through propaganda, lies, obfuscation, etc. so we don't know about it
• powerful lobbying

Here's some examples:

• Cigarette companies spent decades convincing people their product was harmless and Even good for you. The oil industry has been covering up climate change the same way.
• Trains are rarely an option in the US, because of subsidies to planes, roads, etc. Car companies pushed hard to actually remove public transportation.
• Don't like your ISP? Too bad, you probably don't have another choice
• Look at the PG&E story and how they contaminated drinking water, then just lied about it while people died. You don't really have a choice about who supplies electricity to your city.

Yes, you could choose to live off of the grid and walk everywhere and grow your own crops, but that's hardly a choice. And it doesn't have to be that way. Shitty people at the top of these companies make ungodly money by screwing everyone else over anyway they can, regardless of the cost to humanity. That is the point.