The CEO that they overthrew was generous to the employees and was very dedicated to ensuring the brand of the franchise as a supermarket with fresh products and low prices. His policies drove the success of the business, but the current stockholders are old, greedy, and impatient, thus they want to decrease benefits to the employees, decrease staff, and raise prices so that they can quickly squeeze whatever profits they can out of the consumers before they eventually sell the business and reap as much money as they can right away. They have no concern for the future of the company. This faction was lead by the former CEO's cousin, who basically profited off of his cousins success and was still jealous enough to try to overtake the company and kill it while profiting big time.
Unfortunately for them, Arthur Demoulas' policies and practices has build a very strong loyalty from both employees and customers, which is rare nowadays, and their movement to throw him out is backfiring big time.