I like your thoughts here--Something evangelistic would have been good, or something that demonstrates the Goodness of God through Jesus Christ our Lord...Making the church a place of partisan politics? Not for me.
I can think of a lot of signs that would have been more beneficial to all readers. It was done with the intent to ruffle political feathers, not to bring anyone to the Lord. And that's not the job of the church.
The verse in question is not about American politics anyway.
I can think of plenty of people on the "right" who will split hell wide open if they do not submit to God and his gift of grace.
I guess stunts like this, even though I am a right, Republican gal, just make me mad.
John 3
17 For God did not send his Son into the world to condemn the world, but to save the world through him.
Or
Romans 6:23
23 For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord.
But now they have angry atheists blowing up their Facebook Page ratings