To an extent, it is. Americans can’t do much about hay shipped to the Middle East, but buying cheap produce out of season pushes markets to grow crops in unusual places. Less of a problem when buying in-season foods from down the road, but that’d mean customers also have to stop shopping at places like Walmart.
Americans seem to be one of the only two groups that actually could do something about Americans shipping hay to the Middle East, no? How is that a "can't do anything about it"?
Outside of voting for politicians in elections who promise change in this regard (and casting a vote is a very coarse signal), the average individual American can't do much. And blaming individuals for taking advantage of the system they were borne into is dumb—individuals cannot be expected to understand the macro-level naunces that group behaviours have.
Voting is a much worse waste of time and resources than making the right choices. Even if you vote for the "right" congressional candidate, the hurdles of getting a bill out of committee, avoiding lobbying pressures/temptations, making deals with other members of Congress, watering it down with the other chamber, hoping it doesn't get vetoed, etc, already reduces your odds by, let's say, 95%.
If you buy local, in-season, sustainable foods, you have a 100% chance of being 1/300MMth of the solution, not a 5% chance of being that same 1/300MMth of the solution.
I don't live in the Southwest, but I'm not inconveniencing myself so some fucking company can make more money. If the individual needs to belt-tighten, so can the company. They're people too, right?