It defaces private property without consent from the owner of the property. It's like painting someone else's car without their consent. When you graffiti your own property or have consent from the owner of the property it's no longer a crime, just art.

Holo no Graffiti (ホロのぐらふぃてぃ, stylized as holo no graffiti), shortened as HoloGra (ホロぐら), is a weekly animated comedy short on the official Hololive YouTube channel every Sunday.

How a Community is "Hurt" by Graffiti. Graffiti sends a negative message that nobody cares attracting other forms of crime and street delinquency to neighborhoods. It also decreases property values, sense of safety and security and community growth.

Owner's consent: It is only illegal to graffiti, paint, write, or otherwise mark property if the property owner did not consent to it. If your defense attorney can demonstrate that the graffiti, painting, writing, etching or like “damage” was done with the permission of the property owner, the charge cannot stand.