It could also be because they simply can't allow themselves to believe that their argument has been refuted because it was such an essential ingredient in their delusion that they know better than science from their position of ignorance.
It puts me in mind of a 1909 painting by George Bellows called Stag At Sharkey's. This painting represent a departure in American art when French Impressionism and the American Hudson River School, which tended to glorify the American West, were both rejected in favour of the realism to be found in the growing urban slums. It was called the Ashcan School because it dealt with life with all it's grime and ugliness and found something noble therein which the artist could depict using techniques formerly used to depict beauty and romanticism, and so show them to be beautiful and valid in their own terms. The Ashcan School, or "The Eight" later became know as "Apostles of Ugliness", so, for all it's brutal ugliness, which is rather the point of the painting, Stag at Sharkey's is an important painting in the history of Western Art.
Stag at Sharkey's depicts a prize fight reminiscent of a 'debate' with a Creationist where they assume the idea of debate is to score points anyway possible with no concern for honesty and truth. Punches below the belt and gouging are okay so long as it gets them out of the corner or off the ropes. For example, lying about something you said a few moments ago, name-calling, threats and insults or deliberately misquoting or misrepresenting something you just said.
Their tactics more resemble a street brawl or a playground scrap while you are trying to get across some logical point, explain a scientific process, correct a false assertion or bring them back to the point they are running away from, or simply explain that they are wrong and where they can go to prove it for themselves. In all probability they haven't even understood the rules and, even if they have, they've assumed they don't apply to them because, being religious they are entitled to special privileges and exemptions.
But the worst part is when you have defeated all their 'points', answered all their 'unanswerable' questions, shown their basic assumptions to be invalid and based on disinformation, or explained how their questions merely highlight their ignorance and that that is not actually what science says, and they simply hit the reset button and ask a question you answered a few moments ago denying having seen your answer, they simply do not understand, or refuse to accept, that they have lost.
The point of a boxing match of course is to knock your opponent out by giving them enough brain damage to ensure they can't stand up for ten seconds or more. However, this presupposes your opponent actually has a brain which can be damaged and that they are able to register the fact that they are on the canvas and have been counted out, and that that constitutes defeat.
This generally works with boxers, no matter how badly their brains have been damaged by previous fights. However, this analogy seems to break down with religious fundamentalists and Creationists who don't seem to have the necessary equipment for knowing they've even been knocked down let alone that they're on the canvas and have been counted out. Instead, like mindless automatons they continue swinging aimlessly and even proclaiming victory, seemingly oblivious of the mirth of the audience, or even the rules of the game they were in.
But, for all their brutal ugliness, there is nothing noble in fundamentalist Creationism. It doesn't represent a departure or a rejection of an old and outdated idea and the beginning of something new and exciting. It represents exactly the opposite - a desperate clinging to the past and a desperate attempt to pull us all back to something far more primitive and brutal and which was rejected by all enlightened, progressive and educated people more than a century ago. It's like comparing the primitive scrawlings of children who can barely hold a pencil with a Monet, a Picasso or a Ken Howard.
Much of it of course is genuinely childish; the product of immature minds developing in a scientifically illiterate, superstitious culture which still believes in magic and demons. A lot of it is also arrogant narcissism by those too lazy to learn, indifferent to truth and honesty but desperate to be thought of as wiser and more profound in their understanding than people who have bothered to learn and who do care about things like truth and honesty.
But there is also a sinister group of Creationists who are trying to overthrow science and especially Darwinian Evolution because they do understand it and understand only too well the threat it represents to their ambition. They intend to use religious superstition to undermine secular democracies and make a grab for power with the introduction of a primitive, brutal, Bronze-age style neo-Fascist theocracy, under their control, naturally, the artistic equivalent of a simple rock drawing and the cultural equivalent of abolishing the last 3000 years of human progress.