Khalistanis and their effort for an independent punjab is not mentioned in Pakistani media because of a larger focus on all Islamic independence movements like Kashmir. It is a narrow minded and weak policy. Khalistanis want an independent Khalistan and we should support any movement whether it is by christians or sikhs. We only support muslims.
I take it you are not familiar with the history. Benazir Bhutto tried to fuel Khalistan movement but failed miserably coupled with the massive genocide against Sikh population in huge portion in response.
Whereas for Pakistan, Pakistan has full plate at this moment. Bear in mind that ISIS is also joining TTP on Afghanistan to fight against Pakistan with the full-fledge cooperation of India.