Niantic has been removing graffiti and individual disc golf holes simply for not meeting criteria. I asked about how to submit those and was told I could use any reason.
However, when I tried to submit in game reports for disc golf holes, they were rejected. When I use the form linked at the top here for “Reporting Abuse” there is an option there to choose " Fake Nominations or criteria issues", so I assume that is how this was reported for removal. Or, Niantic was just cleaning up the area and removed it.