I'm not an expert on sheep but isn't it pretty much required to shear sheep these days because they don't shed their wool like other animals do? The wool used by Nordwolle comes from sheep that are used for grazing on dikes or fallow land. Apart from Nordwolle there are apparently no other buyers for this wool.
I know that you can make a valid argument against any livestock whatsoever but using sheep to care for the land by letting them do what they do anyways (grazing, shitting and walking around) and selling the wool they don't need can hardly be called exploitation