Well, they are not all ranting and raving in the streets. They are taking part in what is called the political process and exercising their rights as Americans. There are only 24 hours in the day and some make time to have their voices heard. Some are analyzing and writing, some are speaking and some are listening. You might make the same statement about any group; Democrats, Republicans, Environmentalists, vigils for missing or murdered people - the answer to why people do things should be intuitively obvious - they are doing something they think needs to be done. If you really want to understand why a group does something, read what they have to say to gain an understanding of what they believe and why they believe it without automatically dismissing it. You just might find you have some common ground even if you do not agree with all that they have to say. Look at whatever it is from the other person's point of view. Put yourself in that person's (or group's) shoes. Some will be morons and some will have valid points of view. If you automatically dismiss someone else, then you are not genuinely interested in gaining an understanding.