It's a purging of sorts. Like, when you're all done doing your laundry and it's fresh and bright, but washing the clothes, you wouldn't want to get in while it's spinning around.
Legal plunder can be committed in an infinite number of ways; hence, there are an infinite number of plans for organizing it: tariffs, protection, bonuses, subsidies, incentives, the progressive income tax, free education, the right to employment, the right to profit, the right to wages, the right to relief, the right to the tools of production, interest free credit, etc. , etc. And it the aggregate of all these plans, in respect to what they have in common, legal plunder, that goes under the name of socialism.