Why is punjabi language looked down on even by other punjabis

I am a human first than a Punjabi why am i being called a j#hil for talking in my mother tongue? In school's and colleges they berrate you for speaking the"m#lang tongue" and even in own homes families stop you from speaking it. Why? It is literally our language if we won't speak it who will? Was there some propaganda that happened against the Punjabi language that i missed? Why is it known as a cheap language of uneducated people??