Punishment

[Akivah]

Why is it OK to spank an unruly, physically immature, and juvenile person and not an unruly, psychologically immature, and elderly person?

I think the biggest difference is capacity for learning. For a child, their brain is in learning mode. A quick swat can reinforce whatever lesson their parent is teaching. For a senile adult, their brain is decaying and not learning nor remembering. Spanking is not effective as a teaching tool at that time.