It doesn't matter if anyone believes in it or not. Either you're wrong and you're no further behind, in fact, from a trust standpoint, you're ahead because you're now in control of your food supply from the ground to your plate... and if you're right, then you win.
I'm over simplifying to be facetious, but my point stands. If everyone put not only their money where their mouth was, but took legitimate action to ensure their lifestyle fit what was important to their belief, I don't think we'd suffer from half of the problems we do. Unfortunately 90% of the population are happy with just complaining and being armchair politicians and only make the convenient choices that don't interfere with their comfort and their status quo.
If you believe big agriculture is destroying the planet, find a sustainable way to not support them, or support them as little as absolutely possible. Support your local farms and farmers. Support Mom & Pop stores in your local area. Buy from farmers markets. Learn to preserve food over the winter months when it's not available. Eat seasonal produce.
Of course, everyone's lives are nuanced and complicated. It's not as easy as it sounds for most people. But I firmly believe that if you truly believe we have a problem (which I do), then do something about it instead of just talk, complain and continue life as normal.