re: display at state capitol
Okay, I looked into this a bit (that's how I found out about the bust of Washington being used in an idolatrous fashion).
I don't see a problem here.
1) This is a public venue, not private property, and theoretically, ANY belief system should have access to it if it's okay for any of them to have access. Had the sign been a menorah, or a symbol of any other religion, it would be just as appropriate.
2) IMO, the sign is not that aggressive in tone. I saw it as a rather mild expression, although I might have left the last two lines off.
Certainly it's not on the level of "Piss Christ" in terms of shoving a finger up someone's nose.
Just my take on it.