Not to be insensitive, but you might be over-reacting on this.
No one likes to be exposed to ideas with which they do not agree. But in this world, there is a lot of room for a lot of ideas, and you are free to disagree or ignore them at your whim. As you pointed out, you are free to delete the excerpt... it's not hard-wired into the reader. Be glad, I suppose, that no one is forcing you to agree with the excerpt, pay extra for having it preloaded on the reader, or read it every morning upon booting up, in order to own the reader.
The God Delusion, whatever your (or 90% of the public's) personal opinion on the subject matter, also happens to be a best-selling book, which is the reason its excerpt was included on the reader (along with others, as you pointed out). Remember, we're talking Sony: They really don't care about your politics, they just want your money. They're not practicing religious intolerance, they're practicing capitalism coupled with religious indifference.
In point of fact, The God Delusion is also available for the Kindle. And in print bookstores around the world. Singling out Sony for placing an excerpt of it is, I think, being a bit unfair towards Sony... you might just as well attack all bookstores for carrying the entire book.
So don't be so hard on Sony... they are not in the religion business. You bought a reader... that's good enough for them.