You say "working on someone else's plan" is what you mean by "working for". You then go on to talk about selling your labor. These are two different things.

Under capitalism, the capitalist doesn't make a plan. They make a bet. Part of that bet is hiring planners to make the plans that other people will work on. This is why I asked the question I asked.

When you and the manager both sell your labor power to the capitalist for a wage, you both work for the capitalist, but you don't work on the capitalist's plan. You work on your manager's plan.

If you take the capitalist out, and if we define "working for" as selling labor, then "working for" is abolished under socialism, even though hierarchy remains.

If instead the definition of "working for" is "working on someone else's plan", then we have a discussion about the fact that planning is a type of labor. In some context, planning can be done by the people doing the work at the expense of efficiency, which is fine when our goal is maximizing liberty. But there are other contexts where the work to be done and the planning are significantly arduous and complex enough that different people need to do the planning and the execution.

When this is the case, inevitably, anarchists start talking about "voluntary hierarchies" as the correct prefiguration, but this meme is raising the common objections from some anarchists that there is no such thing as a voluntary hierarchy.

Hence, the discussion below about the reality of stratified systems and levels of complexity creating naturally stratified labor distribution, which lends itself to hierarchy.