In Huck's description of the church service and later the hogs that sleep under the floor, do you think Twain is satirizing religion itself or the way some people practice religion?

I think that Twain is satirizing the way that people practice religion.  He is making no social commentary on religion, just the fact that people forget what the real meaning of religion is. I think that the satirizing of the way people practice religion is perpetuated by the way that the Grangerfords and the Shepherdsons constantly fight with each other ev