So .. if somebody came up to your mother or father in a public restaurant and started calling them names .. would you react ..?? Or would you just sit there and take it - because after all .. they only did it for a reaction.
Nobody has to serve my God .. NOBODY .. but to say you're tolerant of all religions and then portray the God of the Universe (and the head of my religion) in such a perverse manner is rude and insulting. I do have a right to get mad.
With all due respect (and I mean that, I'm being sincere), I think there is a difference between your analogy and what this is really all about... I'll try to explain it as I see it.
If you were in a restaurant and somebody disrespected your parents to their faces, then that is a direct face-to-face attack on the actual person you are trying to offend.
Jesus Christ is seated at the right hand of the Father in Glory, and all authority on Heaven and Earth is His. He is not trapped in a piece of paper with a couple of dollars worth of water colors on it, or in a printed publication with a few cents worth of ink on it. Just because the "artist" says that his picture is depicting Jesus, doesn't make it so. It's having no effect on Jesus personally at all. His feelings aren't even hurt by it, except His feeling of love for the people doing this, who He longs to save and heal. By that, His heart is broken.
The biggest problem facing the misguided people doing this is not that they are trying to offend Christians -- it's that they need Jesus Christ to forgive their sins. They need to acknowledge Him as Lord. We should be praying for their souls, because ultimately no sin they are committing is as bad as the ultimate sin of not accepting Him as Lord and believing in the sacrifice He made on their behalf.
But again -- I hope you won't misunderstand my explanation. If you still feel angry with these people, so be it. You're still a believer and I'll still love you in the Lord.