Are you sure you've transcribed it accurately? It would be syntactically correct if it said '...the threat of exitting workers acting as 'veto-players...', but it still wouldn't make sense unless we knew what 'veto players' meant. This might have been defined earlier in the document, or it might have ome special meaning to people who understand the context. It might, for example, be referring to people leaving a position, with the remaining workforce unable to do their jobs without that person. Maybe that's what a 'veto player' is , but the common expression in that case would be 'key worker' or 'key player'. It's not an expression I've ever met.