The link to your picture did not work for me.

I somewhat agree with you based on an LNT philosophy but I think it is a bit extreme to call three rocks stacked in a cairn or other small arrangement of stone graffiti. Some parks allow you to pan for gold or collect a small amount of seashells. LNT is a bit extreme language for what is really a philosophical goal (with some concrete rules depending on where you are). I would rather use graffiti for actual destruction to our parks which does happen on a frighteningly regular basis. In terms of moving rocks, I would call this abhorrently destructive:

https://www.cnn.com/2014/01/31/us/utah-boulder-boy-scouts/index.html

I wouldn't want to use similar language to describe someone trying to help others find a trail.