Well I wonder why? Maybe it was because he was a corrupt, selfish pork-face. Nixon paid the price and did the right thing by resigning. Clinton worried more about himself than the country and refused to resign. And you want to lecture us on consistency?
Why did Nixon resign? Because he got his hand caught in the cookie jar and was forced to. Otherwise he wouldn't have.
You might think that Clinton was corrupt but nobody was able to pin anything on him directly. Remember he wasn't convicted of ANYTHING by a Republican congress other than lying under oath about a sexual affair. It had absolutely nothing to do with corruption. Or is your version of the judicial system that you are guilty until proven innocent?