Decentralized decision-making means no hierarchy. There may be hierarchy on local level in the sense that families, tribes and other relatively small voluntary organizations that comprise the state may be hierarchical, which means centralized, but there is no general organization of, hence no established hierarchy between, these groups.
According to the rule that like conditions seek like conditions, one would expect that an organism that is self-organised will strive to extend its organization to apply to small social units such as family and eventually to larger social units such as nation.
It makes no sense that an organism seeking a local organization (organized self, family, tribe, etc) will not seek a general organization (organized nation.)
Thus, one has to ask, why would someone arguing for local centralization not argue for general centralization?
There are two possible answers.
One is that they are lying. They really want a centralized form of government but they have to lie that they do not do so in order to trick others into thinking that centralization is undesirable such that they lose the desire to enforce their own organization onto others and in this way enslave other people. The argument is that such a lie is a useful protection against slavery.
The other, much more probable scenario, is that they aare disorganized people seeking disorganized conditions. Rather than being clever liars, they are simply people seeking conditions that would offer them protection from their very own mind (unpleasant emotions, thoughts, instincts, etc.) Basically, hedonists seeking pleasure/peace or freedom from self/nature.
Clever liars have a plan. These people have no plan. They are merely doing whatever is necessary in order to calm their emotions.