There is a significant difference between appropriation and stealing.  Stealing is never a good thing because you are taking someone else's idea and making it seem like it's your own work. Copying and stealing someone else's ideas doesn't result in originality and unique photos. Appropriation is okay because you are getting inspired by someone else's idea to come up with your own unique ideas. However, you can not steal someone else's work exactly because that isn't art, it is just stealing someone else's thoughts and creativity.