Beautiful song--great lyrics, and a lovely tune as well.
As an aetheist, I'm no expert on what constitutes blasphemy, but my guess would be that the problems some people have had with the song have to do with their not understanding its use of irony. Every time I see an ironic piece in the press, it's followed by horrified outcries from people who took it literally. So maybe they think the song is a criticism of the Virgin Mary. Then again, it could hit a bit too close to home with some folks who are quick to criticise anyone around them who is "different" in some way.
I say, Keep up the good work!