Just a final touch
For several days, the photographer of this photo watched the hard work done by the artist, showing a horse-drawn carriage and old-timey family atop of it. Artists were gone his way after being satisfied with his job. After two days this awful thing was done to his masterpiece.
Assessing from the color of the spray it was done by the same person who tagged the wall on left said. What is the point of damaging the other person’s hard work, just because you can’t do anything that good?