I agree with those who have said that young adults haven't yet been jaded by experience or discouraged by failure and view a world full of possibilities. They also very often have strong convictions and want to put them into action. Until recent years, my own social activism had lessened from when I was a young adult, but the pressing problems (climate change, gun violence, air and water pollution, etc) have returned me to social activism at a level I haven't had since I was a young adult. So it is possible for loud voices for change to also come from older adults, uniting with younger adults.