In most social situations, we respect those who are recognized experts. If you were at a party and complemented your host's new marble countertop and a geologist said, "Yes, it is beautiful, but actually, it's granite," you wouldn't argue. And if you did, nobody would feel sorry for you for embarrassing yourself by contradicting the expert.
So why is it that on one specific topic, the age of the Earth, creationists feel qualified to overrule the experts? More to the point, why do they drop the usual social norms? Why do they think it's OK to disagree with a scientist on this one topic, something they would never do on any other subject?
A high-school teacher can tell a student, "No, you are mistaken. Here is the right way to understand this problem." From a sociological perspective, the teacher is the alpha, the dominant person, and the student is submissive. There is no social faux pas when the teacher corrects the student. It's not considered arrogant; the teacher is supposed to be more knowledgable and is supposed to correct the student in front of his/her peers. Nobody is embarrassed by this social dynamic.
But when a creationist violates the normal respect granted to experts by making claims that are scientifically impossible, the scientist has two choices: to become like the high-school teacher, correcting the creationist in front of everyone, or to remain silent and avoid embarrassing the host and other guests.
Creationists have huge gaps in their knowledge when it comes to science. It's not merely that they are ignorant of scientific facts, but rather they don't even know what science is. They often assume that science is a belief system, another set of opinions about the nature of the universe, one that's on equal footing with other belief systems.
This is completely, utterly wrong. Science is not a belief system. It is a process. It is a methodology that has proven fantastically useful for centuries as a way for people to find truth and agree on the facts. Science is not about truth – it's about finding the truth. It's a way to ensure that our biases and preconceived notions are minimized, while the true laws of the universe are revealed. Those trained in the scientific method know that it works, and that this incredible methodology has made virtually everything that we call modern possible, from the mango I just ate that was shipped from overseas in one day, to the computer and internet that is bringing these words to you.
So when a scientist appears to be disrespectful towards a creationist, who is really making the social faux pax, the scientist or the creationist? Is it the creationist who, in spite of having no scientific training, is willing to rudely and publicly disagree with a highly-trained specialist, thus forcing the scientist to expose the creationist's ignorance in public?