Airclues, surely the part of the Act you quote is to do with dismissals. Those who have been on strike and who are now due to return to work on a non-strike day tomorrow have obviously not yet been dismissed, nor could they be without giving them notice of dismissal as per their contracts and with good reason (which can't be just because they went on strike).
They could however be summarily dismissed (i.e. without notice) if they had engaged in gross misconduct, such as bullying or harassment of other staff.
Interestingly, "Bringing the Company into disrepute" is also on our company list of gross misconduct offences which staff might want to consider before they appear on TV insulting or infering things about the CEO or other staff member. Mr Walsh has the same right not to be defamed as any other staff member!
