If my goal was to be annoyed on a near daily basis, the New Zealand herald would be my friend. Then again, it's not only the herald that are putting forth annoying non-arguments like this. It was even put forward in the tea room at work yesterday with someone labelling the protestors who occupied a oil exploration ship as hypocrites because they drove there (thus using oil) rather than cycling or walking. And I've heard similar arguments levelled at occupy protesters who use modern tents and electronic devices (like ipads and cell phones).
It's a bad argument. At best, all it does is show how ingrained the thing being protested against is embedded in our lives. In the case of oil and plastics, yes, there's a lot of them in our lives. It does not follow that if we want to reduce their use on a global scale that we have to cut them out of our lives. Indeed, if we did, we wouldn't be able to protest their use. On a personal level, yes it's good to cut the things you don't want out of your life. And I bet a fair number of of the greenies who get slandered becuase they drive a car do actually try and reduce their usage to a bare minimum. If you're trying to reach a population though, you have to use whatever tools are available. If you throw those tools (be they ipads or cars) then instead of changing the population level status quo, you reinforce it because you are no longer able to effect action.
When Al Gore went round the world talking about the Inconvenient Truth, he was pilloried for flying from country to country in a plane that used jet fuel. I would hazard a guess though that by flying from country to country he has done more than enough to raise the spectre of global warming and induce action in the population to offset the carbon expended in the effort. Seriously, if you want to reduce the amount of damage that farming does to our environment, it does not follow that you must then become a self sufficient hippy living on the Coromandel. Doing so would not have any significant effect on the damage farming does.
If you can't recognize that your tools aren't perfect then you'll never be able to make better ones.