Mary and Joseph in Bed?

In New Zealand a billboard at a church depicts Mary and Joseph in bed together. The caption reading "Poor Joseph, God was a hard act to follow". Implying that Mary and Joseph had sex, Mary looking up to heaven as she has sinned and Joseph looking extremely sad.
I am not sure how this billboard was even allowed to go up in front of a church and around this time of year, when the Virgin Mary gave birth to the Savior.The church vicar Archdeacon Glynn Cardy said the billboard was intended to challenge stereotypes about the way Jesus was conceived and get people talking about the Christmas story. I can understand there reasoning since most people have forgotten the reason for this season. But to put such a picture and the message behind it, it's just mind boggling. I would expect this from anti-christian groups who make fun of Christ, and what he is about, but never a church.

If you want to spark a conversation about the true meaning of Christmas, put up a nativity scene or the three wise men or the baby Jesus is a manger. But this, this is too far, with no respect.