the specific argument you put forward is rather weak

I wasn't claiming to pick the most environmentally destructive thing that people do. I was just picking a random, easy-to-understand thing that seems innocuous but still contributes to climate change. People know that driving cars is bad for the environment, but often don't stop to consider that eating a banana could also be bad because of the shipping.

the problem cannot be solved from the consumer’s position

Not completely, but consumers can change their habits and make a significant dent in the problem. For example, "people sitting in tons of steel making short trips". If people stopped driving, or at least significantly reduced it, that would have a real effect.

I'd argue that the problem can't currently be solved by voting either. Yes, government regulation eventually has to be the answer, but right now there are too many people who would vote against that kind of a change, or who at least wouldn't make it a priority. And, with all the fossil-fuel special interest money flowing into politics, even if it is a priority for a voter, there will often be elections where both major party candidates are in the pocket of the oil industry.

If people change their own personal habits (i.e. stop driving) that makes a small dent in the problem. But, it also motivates them to try to campaign, run for office and vote for other people who will make that kind of a change. If you stop driving you realize how much cities are geared around driving. How many hidden subsidies drivers get, etc. If you keep driving but just vote for candidates who talk a good game about carbon taxes, when they back down on those promises you sigh but you aren't highly motivated to keep pushing.