I have to get my two cents worth in on this one. First, I never could comprehend where the concept comes from that ostracism will result in an individual's yearning re-acceptance to the group to the extent that he will endure all sorts of humiliation to attain that goal. It is not reasonable psychology. And here is the caveat. A reasonable person of normal intellect and emotional stability will view official dismissal from the group as the insult that it is, and will continue life separate from the group, developing new and improved societal connections. If, however, the person is emotionally or mentally dependent on the group, he may pursue restoration within. I suppose this is the case with those who fight to become reinstated once ostracized from the group. For them, a more suitable remedy would be some good professional intensive therapy, possibly including some pharmaceutical assistance, aimed at rebuilding self-esteem and a healthy sense of self-worth.
Unfortunately, the self-torture route is so ingrained from the persistent drumming in of persecution, misery, isolation and the like, that many once they reach that juncture may feel that regression (i.e. endeavoring reinstatement) is the only solution.
But, in reality, a mentally and emotionally healthy and whole person who is ostracized from a group will walk away. The ostracism in itself is not going to be of any value to get them to return (if that is what the group wants). What will force them back is their own lack of resolve and personal determination.