Is Graffiti Art Legal?

When did the perception of graffiti shift from vandalism to art?

Graffiti art seems to be the latest craze. The art community has embraced graffiti to the point of commercialization. Growing up in the Bronx during the 80s and 90s, Iā€™m VERY familiar to graffiti. I experienced thhh of the subway art scene (link to article) as but it was always considered vandalism and I do recall the graffiti and gang association. Simply put, it was illegal and it was mainly the bad kids that were tagging up walls.