Can anyone be an artist. The answer is both yes and no.
Because the question may as well be can anyone become a rocket scientist. First you must have the desire to be a rocket scientist, if you do not have the desire you can never be one. Second you must train or act on being a rocket scientist, it is not enough just to want to be one. Finally you must find other people that recognise you as a rocket scientist. If what you do doesn't appear to be rocket science maybe your not a rocket scientist.
So it is with art. You must desire it, do it and then be good enough at it that others must acknowledge that you are in fact an artist. It also helps if people will pay you to do it, but this is not as important as the first 3.
So yes "Everyone's an artist."
But only if they want to be, do it and are hailed as one.