You are right that he SHOULD be asking for an FBI investigation. Why not? He said he wants to clear his name. So, why not? I don't buy the GOP or Trump wish. He is fighting not just for the job of the Supreme Court but possibly the job he has, the coaching he does, his marriage for all we know, his reputation. He could say "The Majority Party and the President don't want an FBI investigation to stall the process". He's not saying that at all. Also, he COULD say, "if I am NOT confirmed, I will demand an FBI investigation to clear my name." He has also not done that.
People say things that they wouldn't under threat of perjury in an official investigation.
Also, I agree that while Dr. Ford seems very credible that as far as burden of proof, unless Mark Judge were investigated and he corroborated her story, Kavanaugh likely could not be found guilty in a court of law. But, we are talking about two other accusations also, and the bar isn't the same as finding him criminally guilty. The bar is whether any investigation or comments from Kavanaugh or Ford or anyone else makes enough Senators decide to vote no.
Now, he just started barking back at question askers "Do you drink beer?" "Have you ever passed out?" Really bad form. THEY ask the questions. HE answers them.
He's guilty of something that he doesn't want known. For sure.