I dont think you would necessarily come off as a jerk for opposing the cross. The question would be to what extent are religious displays allowed in the museum? If the museum, through its bylaws, outlaws religious displays, then case closed. If the bylaws dont address it, then they can be amended but the display grandfathered, if the BOD desires this.<quoted text>
It's a good question and sort of a catch-22. If your against the cross, you come across looking like a jerk. If you're for it, then what next?
American Atheist is, if nothing else, consistent. The main impetus of their argument is separation of church and state. We should all be for that (atheist or believer). The argument is that once you start making exceptions, you are setting a precedent that you know will be taken advantage of at some point in the future.(Case in point - Ten Commandments in court houses, Nativity scenes on town hall lawns, prayers to open local government meetings, etc, etc, etc...)
I happen to take a very black and white approach to this problem. If it's government funded, then you either have to allow displays from any and all faiths (and no faiths at all), or you don't allow any. Obviously, the second option is easier.
The point being that the debate should be over the abstract principal, not the cross in particular. That way, it is more objective, and not tailored to a specific religion.
Also, I wonder if a middle ground couldnt be found. Display the beams, but with no signage. Let the viewers assign meaning to it on their own, if they choose. At the end of the day, they ARE beams.