I went to Pakistan in 1982 on a US passport, without any restrictions on entering or leaving Pakistan. There was a state department warning in effect for US travelers, saying that there was danger in the country and they could not guarantee airport security. That is it.
You are repeating a story made up by someone to support this idea that BO wasn’t a citizen. There are no facts to back it up, because it isn’t true. You can search the internet and find this claim made hundreds of times. However, I guarantee you that you cannot find any objective evidence to support the claim.