It annoyed me when ren keeps punching his wound, but perhaps this was to emphasise the reason rey wins the bout. One thing I noticed watching jedi (again) is paplatine was almost a carbon copy of Potter in its a wonderful life haha
That annoyed me too until I understood that he was doing it to exacerbate the anger in hatred inside of him. I initially thought he was doing it just to show off. Also he did this while fighting Finn and as we know Kylo demolished him.