Something cannot rightly be called knowledge unless it can be demonstrated beyond reasonable doubt. Thus claims to knowledge that come down to belief which is in turn based on interpretation of scripture is not demonstrated beyond reasonable doubt. Thus all that is said and written in the theosphere which amounts to literal claims about the age of the earth, a great flood, and origins of humans is fruit of the same tree and cannot ever rightly be called knowledge.
Science was invented in part as an attempt to ground our ideas about the world in only what can be demonstrated beyond reasonable doubt, but with the caveat that if new information came along that shows this idea to be false, then we change our ideas. Ideas thus formed and tested and that survive this rigor, come as close as we can to knowledge - along with those of mathematics.
If one asserts a religious belief as knowledge, no matter how fervently and sincerely held, you are asserting knowledge where it is only belief, even though you may feel you have good reason to believe it. If you are asserting belief as knowledge, despite - as is the case with YECism - the fact that it has been demonstrated to be wrong then at best you are guilty of ignorance. That is, if and only if you are unaware of the fact that it has been shown to be wrong. If though, you are aware that it is untrue, you are lying.
If you have been shown that the counter-evidence exists but ignore it and deny it and do not bother to fact check your claims then this is a tacit lie. This is a lie by omission, a lie by neglect of effort, and of a positive decision to chose ignorance. This is willful ignorance. This is a lie that you want to deny even exists. There is the lie itself, and, the lie you are telling yourself which is that you are not lying. Then there is the lie you are telling everyone else which is that you are not being willfully ignorant or lying by omission even though you really are. This is a web of lies. This is a house of cards.
People who conduct themselves this way are deceiving themselves into thinking that it is ok to ignore counter-evidence and keep spreading unfounded claims despite not knowing what they are really talking about. This is actively denying other people the truth which is that you actually do not know what you are saying is really true. It is pretending that you have done all the research and they can trust what you say. It is telling yourself that it is ok to do this. These are all aspects of the total deception.
Ultimately for me, this is a question of personal integrity. I would not want to ignore evidence that goes against my current views. I want to know if I am wrong. I want to believe as many true things and as few false things as possible, and I would want to avoid pretending to know things I do not know, or opposing the views of others without being sure of my ground. To me the only thing that is important is that my ideas about the world comport with reality, that they are not based on what I want reality to be, but what reality actually is. Then and only then can I say that what I possess is knowledge.