@Bomoh,
You said:
" .... the note is surely fair comment and an example of freedom of speech."
By leaving a note outside their home with the kind of language on the note, I would call that intimidation, especially accompanied by the puncturing of their car's tyre.
It was an act of a coward or cowards, doing what they had done when the couple was not around or in the middle of the night.
Think about it, other people can also do the same to you for other reasons. I bet you would be pretty upset if that happened to you or your family.
