"The older man who had asked to be left alone"
this never happened. And even if it did it's not the same as saying "get off of my property.“
One's "home" has nothing to do with this situation.
I won't claim to know what constitutes harassment. I don't think this rises to the level of harassment. But, even if it did, I'm pretty sure you can't just deck someone for it.
again, if this were one of Newt's goons, you would all be crying assault.