1. Christians are close minded.
This sounds insulting at first, but hear me out. Christianity demands its believers have faith. To have faith is to believe in your preconceived conclusion no matter what. Faith is the very definition of being closed minded.
A good Christian isn't supposed to consider divergent (aka heretical or blasphemous) points of view. So when a Christian tries to debate me I have to be suspicious as to whether or not they're really trying to have an open minded debate with me or simply trying to blindly argue against my position. In my experience, the Christians I have debated never had any intention of considering my point of view. They just wanted to tear me down so they could feel secure in their dogma and hopefully convert me.
It's not unfair to say "Christians are closed minded," because believing in Christianity doesn't require passive faith in the absence of evidence. Believing in Christianity requires active denial of evidence that proves you're wrong. The next 20 items on his list are ways Christians use logical fallacies and cognitive dissonance to sidestep the evidence that Christianity is mythology.
Belief in Christianity isn't one of those issues where everyone gets to believe what they want and everyone else should respect that. Christianity deserves no more reverence or patience than the mythologies Pacific Islanders made up thousands of years ago. Jesus is no more the savior of mankind than Maui is the hero who pulled New Zealand out of the sea with a fishing pole. Believing either of those stories requires one to deny mountains of evidence. So yes, it's an accurate generalization to say that Christians are closed minded.
I know that sounds harsh, but that's because the truth hurts. You don't have to take my word for it. Anyone can put Christianity to the test. As long as they don't hide behind logical fallacies and mental gymnastics, they can discover for themselves the Bible doesn't hold up.
2. Christians don't play by the rules of logic.
The sane way to think is to analyze the facts in front of you and try to find meaningful and consistent connections in the data to draw consistently reproducible conclusion from. Then, once you've come to a conclusion you should be eager to test it against new evidence to see if it still holds up. If it doesn't, you should update your conclusion until new evidence disproves that conclusion in part or in whole. Wash. Rinse. Repeat. If both members of a debate do that then two people can start with opposing conclusions, analyze the data and agree on a reasonably objective conclusion.
Christians start from the assumption that the Bible is fact and look for evidence to support that conclusion. There's no point having a debate with someone who doesn't question their own data or objectively analyze their opponent's data. It's even more pointless to argue with someone who reverse engineers fantasy data to negate actual, empirical data.
Creationism is full of examples of reverse engineered fantasy data. You can't win a debate with a creationist because your hands are tied with reason and evidence while creationists have free reign to make up unverifiable data on the fly. They can even use data that is objectively, empirically invalid, and they all they have to say to back it up is, "No. You're wrong," whereas a scientific thinker will have to use the scientific method to prove they're right.
Cooking evidence to support your preconceived conclusion gives you a powerful advantage in an argument. Since you're not bound by the rules of logic you can say anything you want, twist anything how you want it and makes excuses to dismiss actual logic or evidence. After having a number of Christians use this style of debate against me I've become extremely hesitant to debate Christians because it's unfair, unproductive, immoral and insulting.
3. There's a good chance they'll use hearsay and/or dubious sources to back up their claims.
Even when I was a Christian attending an overpriced Christian university I recognized that half the statistics and secondary sources my Christian brethren quoted were unreliable. So I was very hesitant to use Christian literature to back up my arguments. Now that I'm on the other side of the fence I've argued against Christians who quote statistics and facts from unverified and unverifiable sources, which is effectively the same as just making up the data on their own. Two people can't have a productive argument when one of them is using made up data.
Similarly, Christians will often use subjective experiences to back up their argument. For instance, they'll say, "I prayed that I would get better from a disease, and I did. So Jesus must have healed me." or "I survived a car wreck, and it surprised the doctors in the emergency room." or "I felt a strong heavenly presence once. So Jesus must be real." These are all examples of basing decisions on emotional experiences, and attributing divine intervention to secular events... especially in cases where doctors saved someone's life using scientific principles. I can't use reason and evidence to argue a point against someone who uses subjective emotions to make decisions that ignore facts.
4. Christians will make stuff up and interpret scriptures however is convenient.
If you ask a Christian how an all loving god could fill the books of Exodus and Leviticus with barbaric rules such as when it's okay to beat your slaves and when you should kill your children, they'll quote Mathew 5:17 "“Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them. I tell you the truth, until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished." Then they'll say, "See, that passage erases all the laws of the Old Testament... except the ones we want to keep like the Ten Commandments."
This passage could mean that modern people don't have to follow all the barbaric and inconvenient laws in the Old Testament, but nobody really knows that for sure. At the end of the day Christians just interpret this passage however is convenient for them and declare dogmatically that they're unquestionably right.
I told a Christian once that the Bible was chauvinistic. He got offended and said that wasn't true. So I pointed out 1 Corinthians 14:34 "Women should remain silent in the churches. They are not allowed to speak, but must be in submission, as the law says." The Christian laughed and said, "No, no, no. Paul was only directing that comment to a single group of unruly woman at the church he was writing to." There's no way to back that claim up. That was just a convenient argument he or someone made up and started spreading around.
A lot of times Christians' arguments sound reasonable, especially when they tell them to you so confidently, but a lot of times, when you scratch the surface you'll find that they can't back their arguments up because they're just convenient excuses someone made up.
5. The Bible is true because it says so.
How do Christians know the Bible is true? Because the Bible says so (or at least it implies it). You can't argue with that. It's logic proof. It's sanity proof. There's no point arguing with someone who can always prove that they're right by pointing at a piece of paper that says they're right. So why argue at all when I've lost the argument before I've even started?