What is a word for deliberate dismissal of some facts? [duplicate]

You can call it a bias. Depending on the person's reason for rejecting fact B, you can use the name of the specific type of bias. For example, if the person chooses fact A over fact B because he already believes in fact A, it's called a confirmation bias.

The tendency to prefer certain facts can be called partiality.

Edit: the relation between the person and the fact they are rejecting can be called denial, and if the person does this often, you can say they engage in denialism.

If the person is aware of the facts and chooses to intentionally disregard them, this is described (originally in legal terms, but also in common usage) as willful ignorance:

Willful ignorance is the state and practice of ignoring any sensory input that appears to contradict one’s inner model of reality. At heart, it is almost certainly driven by confirmation bias.

I like this phrase because it includes the word willful (intentional), which underlines the fact that it's a deliberate choice. To further bring home the point, RationalWiki also notes that:

It is sometimes referred to as tactical stupidity.

To directly answer your question, one might phrase it such:

Do you think he is just unaware, or being willfully ignorant?

I think this is exactly: cherry picking

"Cherry picking, suppressing evidence, or the fallacy of incomplete evidence is the act of pointing to individual cases or data that seem to confirm a particular position, while ignoring a significant portion of related cases or data that may contradict that position." https://en.wikipedia.org/wiki/Cherry_picking