Apparently, love is a happy yellow colored feeling instead of red, at least to whomever was responsible for this bit of graffiti work. One can only imagine what acts took place upon these grounds to spark such a glowing feeling that they had to spray paint that emotion upon this rock?
Of course there were other colors marked upon this rock too (used for obscenities and more gang tagging etc.) so a little bit of desaturation of the other colors helped to cover up or remove the more undesirable spots.