she continues to lie for the same reason all liars continue to lie... to cover up previous lies.
Yes, the first time she tells the truth, she knows it will instantly conflict with any number of things she’s said in the past 30 years, so it’s probably just easier to keep lying. So she won’t waste all that momentum she’s built up!
Also, some of them consider it good, clean fun to keep getting away with it. I think Obama might fit into that category.