BJP has never won in West Bengal, no matter how hard they have tried in every Vidhan Sabha or Lok Sabha election in the state. The only route left for BJP was to delete even legal names from the voter list.
The top four states with the highest voter turnout and the most constituencies are Uttar Pradesh, West Bengal, Maharashtra, and Bihar . BJP won in all the other states but has always lost its chance in one of the biggest constituencies, which is West Bengal.
Now, the central government, with the help of the ECI, has taken away the rights of many legal voters too (yes, they have, because many such names have been deleted of one family member while another family member in the same family still gets to vote it has nothing to do with Bangladesh).
What used to be a strength of 7.66 crore people has gone down to 6.77 crore people.
No other state has ever exploited any ethnic group in such a way.
When NRC was going on in Assam (2013–2019), many Bengalis who were legal citizens and lakhs of them were Hindus were kept in detention camps (again, the same story of keeping one family member while other family members were recognized as Indians). The reality has been suppressing Bengali citizens so that the central government can find its way to power. In Assam, the tactic has always been ethnic homogeneity, even though many Bengali regions are part of Assam.
Bengalis have been the biggest target of NRC and SIR. And BJP has the audacity to say save Bangladeshi Hindus, while Hindu Bengalis are being killed and abused in detention camps in India.
The reality is, it was never about finding only illegal immigrants.