It may come as a surprise but graffiti does have boundaries. Many writers have places where they'd never paint. This could be private property, graves, cars etc. Some people however have no code of conduct at all. If that's your style then rock it, but learn to deal with the consequences. The artist/s in question of painting a space which is "socially not acceptable" receive some negative energy from the community, but are often most strongly condemned by the graffiti community as a whole.