People know their neighbors. Consider that the neighbor might have been known to be anti-social instead (e.g. had one of the subtypes of narcissism) and resolving the issue directly was more likely to lead to a satisfactory outcome for both sides than confronting them because they were likely to escalate / not let go.

Assuming the worst at first is a bad habit but assuming bad intent after a bad track record is established is healthy and helpful.

It should be noted that trespassing near a residence at night, is often different than during the day. Where I live, at night it's criminal.

Where I live it’s criminal day or night, but certainly the likely reactions differ.