For something to be hierarchal in the anarchist sense of the word, it must objectively exhibit three highly specific features:
1. Irrationally authoritarian in nature and vertical in conception.
2. Appointed rulership rather than elective (but not necessarily elected) leadership, meaning the layers above assign authority to the layers below.
3. It manifests as a command structure, meaning it meets its objectives primarily by exercising top down control over the actions of those participating in it, rather than facilitating top down control over a process.
Thus an artisan individualist producer who establishes a business, and recruits people to work alongside him based on their particular skills, whereby those people self-order into a structure that facilitates control over the production process, would not be construed hierarchal at all. No justification for this choice of organisation structure would be sought.
Capitalists have a tendency to phrase things in ways that the classical individualists would not have approved of, such as “work for me” (implying an exploitative arrangement), and use of the term “voluntary hierarchy” to describe what may actually just be an organic self-ordering operational structure. The word “voluntary” is contentious since capitalists define any scenario where someone has given their consent as “voluntary”, regardless of any situational specifics that may have influenced this particular course of action.
Likewise many anarchists forget that although hierarchy is presumed against, it isn’t expressly ruled out, and can be justified where there is no viable alternative to a vertical command structure.