Many anarchists criticism of private property rests on the idea that it is the root cause of the capitalist’s legal right to appropriate the fruits of their employees’ labor. The article shows that it is not. It is the employment contract that is to blame for this violation.

Those are the same thing, though. The author is really putting a lot of stake into the separation of owning capital vs. renting it, and trying to make both of those things distinct from decision making. But ownership is fundamentally about decisions and control. Rent changes that very little. You rent a home, and perhaps get a tiny measure of control over the decisions regarding it, but the landlord retains ultimate decision-making power (buying, selling, renovations, kicking you out, etc.), and capitalism is 100% geared toward ensuring that stays true even in the most wild scenarios we can conceive of regarding tenants' rights under capitalism. And the same remains true of owning a "company"—and, of course, the means of production that are a part of it and keep you from just walking next door and creating a new one if you don't like how the capitalist runs things (yes: this is the part—the enforced scarcity—that makes "owning a company" actually worth something, so it is fundamental to the system).

if you don't think that ownership and control are intrinsically linked, think long and hard about what it would mean to "own" something but not be able to make any decisions regarding it (including where anything produced by it goes). WTF does that "ownership" mean? It's like donating to an infrastructure project to get your name put on a sign by some stretch of highway: it means absolutely fucking nothing.