Animal Rights and Young People (Response to Shelby)

Shelby asked "Did you ever have the revelation of realizing that the meat you were eating was an actual, once living animal? How did this affect your diet?". I can't remember when I made the connection about what meat actually is, but when I was 8 or 9 I became a strict vegetarian (without the help of my parents, something that I now realize was probably dangerous) as a protest of the meat industry. I was very vocal about animal rights, but for some reason people never took it seriously. My parents tried to be respectful, but my brothers, cousins, friends, and even aunts and uncles would taunt me about my decision. They would shove meat in my face, chase me around the yard with it, and make rude "jokes" about my vegetarianism. People also always tried to talk me out of my decision. They would say things like "Oh come on, it's already dead, what difference does it make if you eat it now?" Somehow they couldn't understand that I didn't want to participate in a violent and abusive tradition. When I was ten, I wrote a complaint letter to McDonalds for using animal fat in their french fries. I also "protested" outside of McDonalds with posters I made. Even though I think it's important for young people to start becoming passionate about issues, and even though those things I did were significant in my development as a political and opinionated person, people again treated me as if I was silly for caring so much.

Question 1: Why are people concerned with animal rights often not taken seriously?

Question 2: Why are young people concerned with anything not taken seriously?