Now take a marble slight bigger than the end of a hose and hold it tightly

I don’t see how the heavy granite balls don’t do the same

The giant granite ball is not being held tightly. For your example just set the marble atop the opening of your hose. The water will continue to slowly overflow the end of the hose. Now if you exert additional force on the marble that’s on you.

You should do this yourself and take a video. Share it and speculate with us why the objects in your video behave the way they do.