If you protest something then you are showing your disagreement o your displeasure. After the Gulf oil spill many protested against the oil industry and drilling in the Gulf of Mexico. There are protest quotes about energy, immigration, and even the death penalty. When you participate in a protest you are standing up in a very visible way for what you believe in with the hope that your actions make a difference and force necessary changes. If you sign something or agree under protest this means that you did not want to take these actions but you feel forced or intimidated into doing it against your will. Labor unions in the USA started out in the past with workers who were willing to protest low wages or unsafe working conditions.