Running,
To consent you need to be in a position to consent. Asleep, drugged or unconscious, you are not in a position to consent ergo no consent has been given. The only exception being a couple where it has been pre agreed that they enjoy sex being initiated while they are asleep.
If they were scared or disabled, it would come down to circumstances. If they were reasonably scared of violence, then again, consent under duress is not consent.
It is interesting that you say that no one on MN would object to the scenario that I posited between man and wife. Yet in that scenario, no explicit consent was at any point given, in fact quite the reverse, the only explicit comment was a "no" from the husband. Yet, the wife pressed on and assumed due to the fact that the man was physically aroused that consent had been given. I think that, had I reversed the sexes, a fair amount of people would have objected. And, it is interesting that you object to my post of 9:43, which effectively covers just such a scenario.
Finally as to intellectual argument, let me give you an example:
Person A: No darling, I am too tired.
Person B, But life is short and we should take our pleasures whilst we still can.
That is an intellectual argument in favour of having sex. In any sense objectionable to you?