By that reasoning, there's no such thing as a Friendly human.

True. There isn't.

I suggest that most people when talking about friendly AIs do not mean to imply a standard of friendliness so strict that humans could not meet it.

Well, I definitely do, and I'm at least 90% confident Eliezer does as well. Most, probably nearly all, of people who talk about Friendliness would regard a FOOMed human as Unfriendly.