A federal appeals court has ruled that a Twin Cities Jimmy John's franchisee didn't violate the union organizing rights of six employees fired for publicly protesting the company's sick leave policy, saying the workers were "so disloyal" that they lost their legal protections.

The opinion released Monday by the full U.S. Court of Appeals for the 8th Circuit reverses a 2016 ruling by a three-judge panel of that same circuit.

The three-judge panel had upheld a 2014 decision by the National Labor Relations Board (NLRB), which said the six workers' organizing rights were violated — and that they should be rehired and given back pay. The NLRB's decision in turn upheld a 2012 ruling by a federal administrative law judge.

All the legal wrangling stems from an attempt by the Industrial Workers of the World (IWW) to organize workers at 10 local Jimmy's John's outlets owned by MikLin Enterprises, which is run by Michael Mulligan and his son, Robert Mulligan.

In October 2010, the IWW lost the organizing vote by two votes, 87-85. After the election, pro-union workers continued their organizing campaign, emphasizing their lack of paid sick leave, a common policy in the restaurant industry.

Pro-union workers questioned food safety at Jimmy John's, linking it to sick leave. In early 2011, they put up posters displaying two identical Jimmy John's sandwiches, with one described as made by a healthy worker, the other by a sick one. "Can't tell the difference?" the poster said. "That's too bad because Jimmy John's workers don't get paid sick days."

MikLin Enterprises has argued that poster campaign was "disloyal," and therefore it was not protected speech under federal labor law. The 8th Circuit Appeals Court granted MikLin's request for an "en banc" — or full court — hearing.

In Monday's ruling, the court said that communications in a labor dispute aren't protected by labor law when they constitute a "sharp, public, disparaging attack upon the quality of the company's product and its business policies. … Allegations that a food industry employer is selling unhealthy food are likely to have a devastating impact on its business."

However, the full 8th Circuit Appeals Court agreed with the three-judge panel — and the NLRB — on another key issue concerning the Jimmy's John's union drive: MikLin violated labor law when three of its supervisors encouraged employees and other supervisors to harass David Boehnke, a Jimmy John's worker and organizing leader.

Boehnke was justly fired for his role in the poster campaign, the court ruled. But his supervisors' efforts to "disparage and degrade" Boehnke caused other workers to fear they would get similar treatment if they supported the IWW — a form of coercion, according to the 8th Circuit Appeals Court ruling.

Unions rarely try to organize fast-food workers, largely because they are highly transient in their jobs. But the IWW is a grass-roots union outside of the mainstream labor movement.