If it should belong to everyone as you claim, then every aspiring graffiti maker must ask everyone's opinion before starting spraying.
Graffiti is (partially) just the consequence of not living in that ideal world, but because of all the other problems with graffiti, I'd rather just treat it as the vandalism it usually is in all cases. No sense holding an election before every prosecution or clean and paint job.
This sounds like the words of a “community oversight” committee obstructing the construction of housing, and we already know the effects of that on the housing market. Society has swung too far into allowing other people to tell someone what to do with their property already.
The buildings have a lot more impact then the graffiti, and arguably should have more community voices involved.