A photon is an example of an unstoppable object. When it interacts with nearly immovable objects, it gets deflected or destroyed. (Unstoppable does not necessarily mean indestructable.)
There is no such thing as an unstoppable force (outside of God) or an unmovable object. Thus the argument is rather silly.
I know “me too” posts are frowned upon by many here, but in this case I really can’t help it: me too!
Would not the universe in it entirety be considered an immovable object. I can’t image how one could even define movement of the universe as a whole…
A photon on the edge of the universe’s expansion could be considered an unstoppable object as well…
If you can’t define movement, how can you define it to be immovable?