Kamal Nath, Sonia and Rahul made him CM of MP, but Sikhs still voted for Cong in Punjab. If he is acceptable to them there, then why not in BJP?

BJP's objective is, very straight forward: Ensure Rahul is totally washed out in the North and reduced to single digit in the rest of India and the family don't have any so called safe seat in entire Bharat

This is why BJP is strategically picking Congress leaders. This is also why it took back Nitish and might do the same with Sidhu, Manish too. Every vote, every seat counts. 400 or close to it are needed.

When nation is prime objective, there are no moral arguments here.

If Morals had to be prime importance, Mahabharat would have not won by anyone. Rules had to be broken to establish Dharma