Because he's a narcissist and they can't conceive of a reality where they can do any wrong. When faced with evidence that shows they did something bad, they create elaborate explanations as to why they are not in the wrong. At their core, they are the worst kind of people and it's almost impossible for them to grow as a person. And these days, our society is trying to manufacture them at many different levels. Safe spaces are just one example. Sometimes feeling uncomfortable can teach you something about yourself. Insulating someone from ever feeling uncomfortable when faced with views different than their own or difficult situations helps to breed these kinds of people.

Agreed that he's not going to get convicted of much. I'd add that his incoherent ramblings likely won't change what he's going to get convicted off (jury is unlikely to buy it). However, they might increase his sentence since he clearly doesn't think he's at fault.