If they did indeed have choice and decided to stay there it was their choice. Nothing anyone can do about it.
Like I said most did not have choice and later Pakistan closed the border for new comers and I think the message from Pakistan was that those who stayed there should stay loyal to India.
It is not like Pakistan stayed open for Muslims of India which it was meant for.
Ideology was taken over by economy and job tussle.
Just read about Biharis who really wanted to come back to Pakistan and how they were given cold shoulder by Pakistan and Pakistanis.