I'm sorry you're having to deal with this, Martha. Life is too short to waste it on jerks and bullies.
It may be that he just let LinkedIn connect to his email contacts and auto-email everyone, vs sending a personal invitation deliberately just to you. I haven't played around in Linked In for a while, but I know they had something similar as part of their sign-up process once upon a time. You could either just ignore the invitation, or follow Frank's good advice. If you don't want to link up with him, don't. (He's not worth the hassle.)
In the meantime, keep creating new art and if you have some free time, learn more about how to market your art online. There is a lot of good advice here in the forums. No one else has a say in whether or not you are an artist, that is your calling and your decision only. He can't drive you out of art. If you fear your local opportunities may suffer, then work on building your own opportunities, connections and audience online - the world is a big place and out there he's just a small (and stinky) fish. YOU are the artist.