Jimmy Carter did not ban Iranian immigration like you are proposing. He didn't allow new visas from Iran other than
"for compelling and proven humanitarian reasons or where the national interest of our own country requires" . This was until the hostages taken in the overthrow of the Shah were released.
This can not be compared to a complete blanket ban on the middle east. Carter had a well defined end/goal. I am not sure what HIV positive persons have to do with banning people from becoming citizens because of their national origin. Who is "Oshama"? I don't think that banning people based on their religion and ideology helped the war effort.
Yes, they are very effective. I'm not sure what your issue with the vetting process is. Could you specify? A terrorist could sneak in, but the vetting process makes it very unlikely.