Libertarians promote “natural” hierarchy; the ones based on slavery, inheritance, and other mechanisms of white supremacy. And ultimately, the hierarchy of money which translates to power. To say they don’t believe in hierarchy when they’re the party of the robber baron who believe the bosses have the right to murder striking workers, even child workers, is frankly silly.
It’s not on anarchist ideology really because of this and only appeals to disinfranchised people if they haven’t bothered to do the math.