“The workers have been called … to protest against the dismissal.”
I would say “called up”.
What is the right choice between “called out” and “called up”?
Thanks again.
‘called out’ here means that the workers’ union has told them to take strike action.
I would expect ‘called out’ in this particular context - they have been called to take strike action over the dismissal, which is seen to be unfair by the workers/workers’ union.
‘called up’ works when talking about the conscription of men into a particular force.