I moved this to the main YouTube Chat discussion forum.
When I switch a video from private to public, I always have to click the "save changes" button (from the "edit video" page) and wait about 20 - 30 seconds before it will switch over to public.
If that doesn't work, then I don't know...maybe try again tomorrow? Sometimes things are a bit buggy... :/ I'm not sure why YouTube might force a video to be private. The only thing I can think of is that perhaps a video is forced to be private if it contained copyrighted material that was blocked in your country. But I thought they'd delete the video outright if that were the case...so I don't know why it might be doing that.