Yes, Alison, you are correct 

Bottom line is they attacked me, continued to attack me, and offered no constructive suggestions.

If you want to communicate something, it will generally be better received if you send a clearly articulated note, rather than spray-painting a message on the side of a building.  Most will respond to graffiti with a new coat of paint to remove the aethetically offensive message (regardless of its content)  They not only spray-painted on my wall, but made some rather unflattering and unhelpful remarks.

In the spirit of "good faith," since they believe that they have all acted in good faith, my wish for them is that everyone they ever encounter for the rest of their lives treat them EXACTLY as they have treated me.  -)