Everyone should have a cause. When my cousin picked up protesting Scientology as his cause, at first I thought that was pretty stupid. Then I thought to myself, "you know, someone who has Darfur, the independence of Tibet, or curing cancer as their cause might say the same thing about my volunteering at the animal shelter as my cause."
Every cause is importance, and I don't think anyone is qualified to judge the relative importance of causes. Not only that, but even causes that might be less "significant" need people, and everyone has different talents and interests. You don't tell me that my cause isn't important, and I won't tell you that yours isn't.