We have lots of stucco down here, the process is typically more involved. You'd have to sand that portion of wall, retexture, then paint over it. People like to pretend removing graffiti is trivial, but it's really not. $4000 is probably a bit more than labor (including paying someone to coordinate with the contractor that does the work) and materials, but the tendency is to overestimate vandalism damage (usually by estimating it as the loss of property value), especially if insurance covers the fix.

This is in NM, there's probably also the added cost of someone's cousin wanting a nice payday, and the building owner passing that inflation on to the tenant/insurance.