Recently The Washington Post published an article claiming that the “widening gap in life expectancy” among America’s seniors “reflects perhaps the starkest outcome of our nation’s growing income inequality.”

Income inequality has become an absolute evil that can be blamed for anything terrible in this world. From slowing down the economic recovery to high hospital admission rates to “killing the dinosaurs,” income inequality, we are told, is at fault.

But there’s no need to be alarmed about income inequality. Our response to the disparity in incomes ought to depend on the underlying causes of the phenomenon: Surely inequalities that result from systemic injustices are different from those that arise from the natural diversity of human behavior.

Income is a brute fact that, by itself, does not determine our course in life. The cultural environment in which we are raised—our families, communities, and schools—also profoundly affects the behaviors that define our lives.

For example, the newspaper’s proof in this case supposedly comes from two neighboring Florida counties: the “prosperous” St. Johns County (average household income of $60,841) and the impoverished Putnam County, where the Post notes “life is neither as idyllic nor as long” (average household income of $33,300). Men and women of St. Johns can expect to live to 83 and 78, respectively, whereas the life expectancy for Putnam residents is 71 for men and 78 for women.

While it is a plausible—if unoriginal—theory that the difference in longevity is a direct result of unequal pay stubs, a study cited in the article identifies a more compelling explanation of the difference in life expectancy: health behaviors.

It turns out that adults in Putnam County are nearly twice as likely as adults in St. Johns to smoke, be obese and physically inactive, and have chlamydia—characteristics that might have something to do with the difference in longevity.

When we look beyond the provocative headlines, we see a fundamental error of income inequality alarmists: studying society as an abstract collection of static income brackets obscures reality and ignores individual choice, responsibility, talent, and effort.

As author Charles Murray has explained, the most dangerous inequality in America is not economic but cultural, diverging along lines of core values, habits, and behaviors.

America promises equality of opportunity, not of results. So the best way to fight income inequality would be to remove the obstacles to upward mobility that still exist.

We should focus our attention on the bottom 20 percent, not on the top 1 percent. By promoting the principles and policies that increase economic freedom, improve the quality of education, stabilize families, and foster hard-working, responsible citizens, policymakers could make life better for those who are struggling.