Taking just the aviation industry as an example, if an airline's workers go on strike people are still left with other airline alternatives. ATC is a different matter. It's an essential service and any disruption results in millions of people going about their lawful and necessary business being affected.
Anyone who wants to take on this vital job must be made from the beginning to understand and accept that they are not permitted to strike or take any other form of industrial action. If they don't like that then they can bugger off and do something else.