Why can't Asians people speak up?

I don't understand why Asians people don't speak up. They get pick on and they don't do anything about it. I was in Chinatown one day. There was this white man he push an old lady on the floor.There was so many Asians people there. They just stood there and watch. I was so pissed off I started yelling at them. Telling them this could be your mom, aunt, grandma etc. They didn't even help her. I get picking on and people are surprised that I start cursing at them. I hope in the future Asians grows some guts to speak up!! I'm tired seeing Asians people get pick on.