I certainly agree that there's MUCH more that needs to be done to truly reach sustainability, and I certainly advocate them. The reason why I've chosen such a narrow focus is that it's easier.
I imagine that I'll get more people to think about their consumption if I ask them to almost entirely stop driving for 20 days than if I asked them to
- Stop driving
- Stop buying food that is transported or out-of-season
- Do thorough research on every product you buy to avoid corporate abuse
- Move within walking distance of your friends and work
- Grow your own veggies
- And the list goes on
It's a just a matter of ease. I'm pretty certain that I can't get many people to completely turn their lives around, but I am fairly certain that I can get many people to change one element of their lives. And the focus on a limited time frame is just the same thing. It's easier for someone to imagine stopping for 20 days than stopping forever. Hopefully, some of the habits will stick (and people will just plain think more about how much they drive).
I'm going for small-scale change. I'll leave the big stuff to the professionals

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Conflicting information really is a large obstacle. It really burns people when a figurehead (let's say Al Gore) isn't "practicing what he preaches." Or to continue with that example, that facts presented as...well, facts, are exagerrated. Instead of taking the spirit of the message, many people will assume the whole thing is hogwash.