This implies that they have some "hidden" agenda that this "willful ignorance" will help them to attain.Well, it's just that my experience with the arguments of garden-variety creationists tells me that most of them don't know much about science, but they trust that their religious leaders & religiously-inspired authors/lecturers do know what they're talking about and that they are telling them the truth.
Would you like to elaborate on this?
The creationists are convinced that morality & societal order depends on creationism being true, because their religious sects tell them that the natural world provides no objective criteria by which to judge people's actions as good or bad. If this is so, then there's no way to adjudicate disputes, and it'll always turn into rule by whoever's the most ruthless in pursuit of their goals. Therefore, "if God didn't exist we'd have to invent him".
When a person is motivated by such a (misguided) fear, that's a strong motivator for refusing to understand something that seems contrary to it.
Actually I served up this softball for you because there are people who are not ignorant, but act as if they were because of their "hidden agendas". They purposely fight what they know is right and good to either advance themselves or prevent the advance of those who are, or that which is, deserving. These are Toohey evil people who prey on the simple minded for their own aggrandizement.
Lest you think these do not exist, I can say that I have met some. I would rather be in a pit of vipers than anywhere near them. And I think there are some here, too.