Our front retaining wall and stairs sometimes gets tagged by nefarious souls, and the other day I tried removing the paint. The pressure washer was ineffective and actually made things worse because it cleaned all the dirt and moss and whatnot off the wall and made the graffiti stand out more.
So then I got some textured spray paint that apparently makes surfaces look like “stone” at Home Depot (btw one apparently must be over 18 to buy spraypaint). It actually worked very well in covering up the paint. The sections I painted over are lighter/whiter than the rest of the wall, but I imagine that weathering will eventually even out the colors.

I win!