Laws are made by people. Those legislators sometimes respond to shifting Overton windows. Your actions and motivations can make a small difference. More actions makes more difference.

Consider the Suffragettes. Few people today would think women should be deprived of a vote. In the early twentieth century too, many thought it would be a good idea, but didn't want to make any personal sacrifice for the cause. It took single-minded actions of a few dedicated individuals and their tacit support by the majority to drive the necessary changes.