You seem to think these are interviews or conversations intended to foster understanding. They aren't.

“Do you support it being legal to abort an unborn child up to the moment of birth?” That’s not really a yes-or-no question

You're right, it's not. It's a trick question. The senator wants a "yes" or "no" that can be used in a good clip or sound byte. Any more complicated answer is useless to them. Since they aren't interested in a real informative answer they just steamroll on to the next potently clip-able question, because they only have a couple min for their turn to ask questions.

On the other side, sometimes it's the one answering who's being disingenuous. They can give a long rambling response meant to run out the clock, rather than honestly answer. In that case the senator asking questions might want to move on because they recognize a non-answer, and again only have a couple min for their questions.

The primary problem in both cases is the time limit of the questioning. It's the very reason most of these senate testimony hearings are such a farce. A real hearing can take days or weeks to interview a single person. But that's too much to ask of congress apparently.