They follow their leaders basically. Look at the pattern of avoiding claiming responsibility like the plague as it ends up with all of the downsides. When borderline the 'not illegal' legalist ethics prevail across all segments of upper society, with Congress sticking to that and blatantly illegally insider trading or worse instead of a higher 'avoid even the appearance of impropriety' the shit has rolled down hill.

Although it might also just be an impact of illusions of nobility from the past shattered by increased transparency. George Washington abused his power to land speculate for one, presidents who had their affair participant institutionalized for stating uncomfortable truths about whose child was whose.