That could be due to internal migration. Just because one division goes down does not mean they all went to India. More likely they left for the Middle East and East Asia or Dhaka or Chittagong.
If that was the case then atleast one other division would have shown double the increase.
In ten years time, the population of BArisal division didn't increase at all, it decreased, at the same time population for other divisions went up by around 4-5 million each. Thats a huge difference.
That many Bangladeshis are not in middle east. They went somewhere else. You said if Bangladeshis did migrate to India, it would show in population growth rate, and it does surely in the case of Barisal.
And I remember proving it to you guys before that even if say 5-10% of the total population of Bangladesh migrated to India, it wouldn't reflect as much on the annual population growth. I ll see if I can find that post for you.
The type of migration you are taking about does not appear in our census after 1987. As I said before significant migration to India too place before 1987 and were mostly Hindus. You now treat them as citizens of India while discriminating against the vastly smaller inflow of Muslims from Bangladesh who really are not migrants but mere visitors who have family links to India that predates the 1947 partition. Simply because they are Muslim you have to exaggerate the issue while ignoring illegal Hindu migration to India pre-1987 which constitutes the most significant inflow into your country.
Once again, its our country our rule. Muslims got their own countries in 1947, we are not under any obligation to take them in, just for the sake of it. If they are being persecuted like "Bihari Muslims in 1971" then fine.
Now no group be it Hindu and Muslim, should be allowed in. Unless of course the people/group is facing persecution. We can't afford to.
You can't divide the country and then come and say, hey why don't you let us in, this is discrimination. Secularism and fundamental rights are for the citizens of the country, not for the outsiders.