"Cathy argues that the use of algorithm in some contexts permits a new scale of harmful and unaccountable systems that ought to be reigned in."

Algorithms are used by people. An algorithm only allows "harmful and unaccountable systems" if people, as the agents imposing accountability, choose to not hold the people acting by way of the algorithm accountable on the basis of the use of the algorithm, but...that really has nothing to do with the algorithm. If you swapped in a specially-designated ritual sceptre for the algorithm in that sentence (or, perhaps more familiarly, allowed "status as a police officer" to confer both formal immunity from most civil liability and practical immunity from criminal prosecution for most harms done in that role), it functions exactly the same way: what enables harmful and unaccountable systems is when humans choose not to hold other humans accountable for harms, on whatever basis.