Because you not post message that response from facebook
What I see that you miss is
>>> g.post(
... path = 'me/posts',
... message = 'Hello'
... )
You use incorrect path. If you debug the error you will got
{
"error": {
"message": "Unsupported post request.",
"type": "GraphMethodException",
"code": 100
}
}
The correct path to post a message to your wall is me/feed
You can test it here https://developers.facebook.com/tools/explorer/?method=POST&path=me%2Ffeed
>>> g.post(
... path = 'me/feed',
... message = 'Hello'
... )
If it still get the error, your problem might be not have publish_stream
permission
For more information : https://developers.facebook.com/docs/reference/api/publishing/