@drahardja ultimately I don't think anyone (credibly, anyway) claims that any of the "general strike" calls this author complains about were successful. But again, that doesn't inherently de-legitimize their intentions.
Instead of saying "leave it to the #unions", I would say, "keep trying" and "talk to your friends and like-minded people". #Organizing is ultimately about relationship-building and #solidarity. No one "owns" the idea of a strike, general or otherwise.