Possible reason why people were so offended by the Iowa bus ad?

I'm mad as hell about Des Moines Area Regional Transit (DART) deciding to pull the "You are not alone" bus ad after a single day. It's absurd that people would be offended by the least innocuous of the three common atheist ads, one that really doesn't make a statement any more profound than "atheists exist."

Apparently people were refusing to board the bus, which I ascribed to the height of bigotry... and still mostly do, though now after reading an article in which the Iowa governor blathers on a about the "message it sent", I wonder if an unfortunate confluence between the ad's layout and the standard DART artwork could have exacerbated the problem.

"All aboard, fellow atheists!"

In the image on the right, the art on the bus makes it appear as though there is an arrow coming from the ad and pointing to the door of the bus. Maybe this is a stretch, but I could almost see people taking this to imply that the full message was, "Don't believe in God? You are not alone. Come join us on this bus!" If people took it that way, okay, I could see them being made uncomfortable.

Am I letting my imagination run wild here? The only reason it occurred to me is because when I first glanced at that picture, I thought to myself, "Huh, I haven't seen the version with the arrow before. Where is that supposed to be pointing? I don't get it..." I didn't extrapolate it all the way to "Come ride the atheism bus!", but my fallible human brain had briefly perceived the arrow as being part of the ad.

Now, any reasonable person, even a theist, ought to quickly realize the arrow had nothing to do with anything. But given that some people are so fucking crazy they won't even buy something if the cost comes to $6.66, perhaps some of the Krazy Kristians thought it would be bad luck, maybe even inviting a lightning bolt from the clear blue sky, if they were to even briefly stand so that an arrow was pointing at them unintentionally implying a disbelief in God?

It wouldn't make me any less pissed if this is true, but it would make me slightly less confused...