Identity and culture is what drives nepalese speaking people of west bengal.
The issue of gorkhaland was always a sore subject for many nepalese people. Nepal never lost darjeeling or sikkim to India , it was lost to british when they ruled India.
Officially India never conqured those parts and should have been returned to Nepal when british left the country but why would they ?
They couldn't even let India be left Intact .Even going as far as cutting out contact from Indus Valley . We as a follower of hindu religion know the injustice of it.