If you ask me if the sky is blue and I say the ocean is a beautiful color today, that would make me incoherent even though you can understand what I'm saying.
Ok fair enough. But If you ask me what colour the ocean is, and I ask "did you ask what colour the sky is" and you either nod or remain silent, then when I answer "it's grey because it's cloudy", it's hardly my fault I'm incoherent.

If he didn't ask for clarity, you'd have a valid point.

Again, you are making Trump way smarter than he is.
Once again, in your opinion. I don't think he's as smart as he thinks he is, but I think he's smarter than you think he is. Regardless, how smart either of us think he is is very much subjective.