Why are introverts/quiet people often negatively perceived?

In my opinion, it's ridiculous to believe that just because someone is reserved, taciturn, nonchalant, and quiet, that means they're mean and cruel. How's that proof that the reserved person is cruel? Usually those who are quiet don't show emotion and it's hard to tell what they're thinking. i myself am an introvert. I was only mistaken to be a sociopath demon spawn once for being an introvert. One time when I was in the 7th grade, a friend of mine (she's a year older than me, she was in the 8th grade when I was in the 7th grade) told me that her closer friends trash talked me because I was so quiet. I didn't take it seriously until I sat at my friend's friend's table and I didn't realize that her friend's were there. My friend told me to hide myself from them. When I met them for the first time(I sat at their table cuz there was nowhere to sit) one of them said "What is she doing here?!" to my friend. Later on they realized that they were wrong about me when I revealed my emotional side. Another friend of mine who is much closer told me that people should judge introverts negatively. I just want to know why introverts are often negatively perceived and viewed as evil people. Isn't the reason introverts are negatively perceived because it's like the silent treatment? You give someone the silent treatment because you're mad at them. I'm not trolling, this is serious. Please tell me.