I disagree with your main point. The petitions are a good idea. We know that some petitions are not going to change the government's mind. But just having a mechanism for getting the government to consider something and provide an official response is a good idea. Previous administrations would simply ignore things they were not interested in. And journalists who get admitted to white house press conferences can often be counted on to completely ignore subjects that were of no interest to either political party.
That being said, petitions do not solve everything and the other political actions you mentioned may be called for. But even then the petition helps, as it provides an official government response which may galvanize other political action.