It has two posts on the hand rail. Spinning is not an option. You're right.....it will come out eventually.....LOL, one way or the other!!!!
The bottom of that rail is not sealed so the above idea won't work on several levels.
Most of all, it is very unsafe and should be disregarded.
Usually it is sand or grit that gets wedged in there. Do you have a pressure washer that you can use. A high pressure washout of that socket may be all it needs to release your handrail.