Uh, I think Agnostic came from A-Gnosis, which is more specific than just "I don't know".
And that's where you're wrong. If you want to quibble that gnostos means "knowledge of god", rather than just general knowledge, that's fine, but even then it doesn't change anything about my point. The word predates the religion of the same name, so if your assertion is that the word came from early Christians, you are incorrect. Agnostic literally means I do not know about god. I don't know if it exists, what it eats, where it lives, what it wants, etc.
What it certainly DOESN'T mean is:
* Rejection of all religions based on books that claim to contain the revealed word of God.
* God exists, created and governs the universe.
* God gave humans the ability to reason.
* God wants human beings to behave morally.
These are points non-religious or anti-religious theists would argue, not agnostics.
My point was that what Train thinks of as an agnostic or an agnostic ideal, is not, only an anti-religious one.