Scottaschultz, I don't mean to pile on, but Housezealot mowed a lawn, nothing else. He did not threaten or even approach the woman. She objected to him mowing the lawn when she had her car parked outside and threatened him with her mace.
I don't need permission from the neighbors to mow my lawn, and I don't expect them to object in any way (if it is a decent hour) and certainly not to threaten me over it. And if I hire someone else to mow my lawn, that is still my business.
Housezealot restrained himself, apologized as far as was possible with such an unreasonable person, and de-escalated the situation. It was his option whether to call the police or not, and he elected to be nice to the woman who was extremely rude and threatening - probably to the point of it being a criminal violation. Someone really needs to talk to the woman, but Housezealot probably is not in a position to be the one.
Such an inappropriate response may be cause for a mental health evaluation, so if HZ is in contact with someone who can approach her, great. Otherwise it is over.