When you create something original you feel like it belongs to you, it could be a piece of art, an oc, or an object you created out of boredom. Now take that mindset and apply it to an overprotective artist. what you get is an artist that believes that if they create something no one else is allowed to copy them. These "copied" pieces of art could be simple things such as color palates character designs or even the smallest of details such as a symbol. Even one similarity can trigger an angry response from someone, "Oh sure, you created an oc with a scarf well guess what there's A THOUSAND OCS with the same one". What im saying is that if you created something theres a good chance that someone did it before you. and criticizing artists for "Copying" their art only degrades originality. However there is a very fine line between this and stealing art, but thats for another time.