Agreed, the letter was overboard but at the same time, who knows how bad it really was/is, and not fair to any neighbourhood to have a mentally ill person sitting outside wailing and screaming all day long, maybe the person writing the letter just snapped because they were so fed up of listening to it.
I used to have a schizophrenic nieghbour and she thought people were wire tapping her house and could hear them whispering, so she would sit in her house with the windows open screaming obscenities, and going off as if someone was murdering her. She would do this all day, and there was nothing the cops could do about it. She lived 3 houses away and you could heat every word she was saying, in broad daylight, kids and families outside playing.