That isn't art, it's attention whoring. There's a big difference between doing something cruel and reprehensible so people watch and react (which is what this guy did) versus creating something remarkable or inventive which moves people (which is what art is supposed to be).
Yes, art is symbolic. Yes, art imitates life. Yes, art can evoke grief and sorrow as much as it can evoke happiness and laughter from its audience. However, you cannot get away with harming, hurting or killing living beings and claim you're symbolizing or depicting something. Art is creation, not destruction. What he did is a punishable crime which cannot be rationalized or explained away under "artistic license". The guy is basically sick in the head and should be locked away for his and others' good.