Why do people who drive crazy always blame others for crashes?

Because they can never accept responsibility for their actions. I was in the Military Police and investigated accidents you just wouldn't believe the stories they came up with. One person said it was his fault because he was drunk. He may have been drunk but you caused the accident.

Likely because they are not right in the head enough to see that they themselves are responsible.

Irresponsible people tend to also not be mature enough to take responsibility for what they do

I don't know. I was stuck behind this woman who missed her turn and then pulled back into my lane. I stopped, giving her plenty of room, then smash, some guy ran into me and drove me about ten feet into the woman I was behind. He got out of his truck and asked me what happened. Duh!