The Bible says this about nonbelievers:

They are darkened in their understanding, alienated from the life of God because of the ignorance that is in them, due to their hardness of heart. (Eph 4:1

It is my sincere belief that this is a willful darkening of their own understanding.  This is ignorance by choice.  They aren’t trying to understand the Bible in its social context.  Instead, they are looking for reasons not to believe in it.

In this post from the Penitent Atheist, this ignorance becomes obvious:

As we all know, Jesus tells us to love our enemies and, if someone should strike us in the face, he commands that we invite that person to have a go at the other side. Now, as wonderful as this idea sounds in theory, most sane people understand that in practice this approach would be highly dubious. In fact, even committed Christians consider these commands to be so impractical that they willfully ignore and disobey them.

. . . Christians teach their children to defend themselves because they understand that a child who acted as Jesus commands would come home bloody and without lunch money, and even worse, without dignity. But let’s set aside the children and just talk about us adults. Jesus does not even allow us to hold up our hands in defense; we must open ourselves and invite second and third attacks. Who does that?

The PA isn’t the first person to have this type of an objection.  J.P. Holding had to answer a similar objection from the book Atheism: The Case Against God by George Smith.  This is what Holding has to say:

The “slap on the cheek” is a type of personal insult, so that the command to turn the other cheek is essentially a command not to start trading insults, but take the higher ground and turn away from the exchange. It is not, as many Skeptics have supposed, a license to allow yourself to get beat up. (source)

The PA is taking things to the height of illogic.  He starts with a complete misunderstanding of what the Bible is actually teaching.  My advice to him would be to try to learn what a problem teaching means before he posts something that looks completely ridiculous on his blog.