They aren't really on strike though are they? Reading between the lines in the statement of claim seems to indicate the airline is dependant on crews working Overtime to fulfil their schedule, and it is simply crews refusing this OT that is causing the majority of the issues.
Pilots - like any employee - have aright to feel safe both at and away from work, and if there is threatening behaviour towards any pilots accepting any OT lines, then no one can blame the rest of the pilot group from refusing said duties.
When your business model is dependant on employees working overtime to maintain the schedule, best you keep said employees happy, lest they decide their RDO's & family time is more important than a few hours at double-time!