If you fly for the sort of company that takes on work when other companies strike, and you want your company to survive, you have to do the work. What are you supposed to do, refuse to work and watch while your company collapses around you? Being a "scab" is irrelevant.
Remember the British charter companies that flew in Australia when Ansett and TransAustralian pilots went on strike? At least one company, Paramount, desperately needed the work. Mind you, not many British pilots could resist the call to stay in some of Australia's top hotels on top allowances and work in the sun all the way through a British winter!