KPS is (was) a school in WB, India. Once it was a good school, but now it is just a shell of its old self. Inside there are no teachers, so students (gangsters) visit there for doing drugs, as schools cannot be raided by the police. So people use the term KPS as a negative sense, just to offend a person, and to make them realise that they are not the same person they were in the past
If you don't listen to the elders, one day you would end like KPS