Religious Profanity

So I'd really like to know the following:

Jesus H. Christ: Is this really swearing? What does the H. stand for? Did Jesus have such an embarrassing middle name he changed it to an initial?

Holy Shit: Is there something special about a holy shit as opposed to a regular shit? Does it smell less? Is it a welcome shit? Does it grant miracles?

God Dammit (and it's spelling variations): I don't see how this is swearing. You're simply asking God to damn something, and from what I can tell and from what lots of Christians seem to say, God is pretty into damnation. I think he probably likes this one, it keeps him busy and let's him know we care about all his hard work watching down on and condemning sinners.

Oh my God: This one seems pretty mild, but some people seem to consider it blasphemous. I don't understand it either way. It's an incomplete thought. When someone says "oh my god", that's usually the end of it. God must get pretty annoyed, it's like the heavenly equivalent of the prank caller I think. You call him, but you never let him know what it is you're calling for.

Anyway, I swear to god on a pretty regular basis. You may ask God to damn it if you like.