Premier Foods - Are they exploiting their monopsony power?

Pay and stay - is this an unfair, exploitative example of the monopsony power of a giant food business over their suppliers? Or a suitable strategy for a company looking to trim their list of suppliers and build longer-term commercial relationships? On the surface it doesn't look good, perhaps the tip of the iceberg in food and drinks industries where suppliers are pathetically dependent on mass-volume food manufacturers for sales?