No, it's not hanging in a museum with a fancy little sign depicting the artist, year it was made, materials, and why it is significant, but graffiti is art. Plain and simple. Merriam Webster defines art as "the conscious use of skill and creative imagination especially in the production of aesthetic objects". There's a reason why we call people who do graffiti, "graffiti artists" and not "graffitists"; I mean come on that just sounds wrong. They are artists in every aspect of their art.
Graffiti is not conventional art by any means, but it is a creative way to express a certain demographic's opinions, lives, or subject matter. Picasso did this with cubism, Van Gogh showed how even people with mental illnesses can do art (and can do it quite well--shout out to the favorite artist), and graffiti artists express their emotions through their artwork on the streets. It's not glorified artwork, but neither was Van Gogh's work during his lifetime.
Even if there is obscene language or gang signs in their work, so be it. There are tons of nude paintings or hidden treasures in famous paintings. It's a part of life, part of a culture. Not something that can be denied or swept under the rug. I mean if you think a gang sign on the side of a highway is bad, go look at the famous painting, "The Kiss" by Gustav Klimt. Found it? Good. Take a good look at it. Welcome back. Scholars believe that this painting actually depicts the man about to sexually assault the woman. That painting is worth 135 million dollars. But, this article isn't about bashing other art, but that was just a fun art fact.
Graffiti is here to illuminate a lifestyle and culture that is otherwise taboo in our society, the underground society. This could be gangs, homeless people, or others cast aside by their communities. Graffiti is used to communicate using symbols, words, or even pictures to others about that area or just a simple way for someone to express their talents in a welcoming way. You can't expect graffiti to be perfect by any means, but that's how art is in a sense. Not everyone gets art or a certain artist's work and that's totally okay. Same goes for the entirety of graffiti; it should not be overlooked because it is an art form.
Okay, the last fact: go look up "Fountain" by Marcel Duchamp. Notice how it literally is a urinal, with some writing on it. Duchamp signed his alias and the year. Graffiti style. One of the eight replicas of this work sold for 1.7 million dollars. Graffiti is art and anyone denying that simply cannot see art for what it was truly designed for: the people.