Hindi Language

In my opinion, Stalin is very true to the core. My point is that if we go to North India, we should learn and speak Hindi. But, why the same North Indian people can't learn and speak our language? And also in Hyderabad, from my personal experience, a lot of shop owners etc are speaking in Hindi pretending that we know hindi being in a telugu state. Being a shop owner, why they can't learn telugu to deal with customers. So what's your take on this?