What do the real Christians that you know say about that characterisation? I don't know any well enough to know what they think

They think you should try and make sure it's really God (they give conflicting answers as to how, mostly involving your own moral judgments which seems kinda tautological) and then do as He says. Many (I think all, actually) mentioned the Binding of Isaac. Of course, they do not a believe they will actually encounter such a situation.

just from general knowledge of the doctrines I understand that the sources of knowledge of God's will are the Bible, the church, and personal revelation, all of these subject to fallible human interpretation. Different sects differ in what weight they put on these, Protestants being big on sola scriptura and Catholics placing great importance on the Church. Some would add the book of nature, God's word revealed in His creation. None of this bears any more resemblance to "direct orders from God", than evolutionary biology does to "a monkey gave birth to a human".

AFAIK, all denominations of Christianity, and for that matter other Abrahamic religions, claim that there have been direct revelations from God.

Now look at what you had to do to get that answer: reduce the matter to a tautology

As I said, simply replacing the word "God" with "rationality" yields clear nonsense, obviously, so I had to change some other stuff while attempting to preserve the spirit of your request. It seems I failed in this. Could you perform the replacement yourself, so I can answer what you meant to ask?