It's an interesting point. With Clinton, l'affaire de bj was a willful attempt to take the president's private life public as a means of congressional focus. It should be noted that until then, this was effectively off limits. It was an open secret in DC that his predecessor, Bush the 1st, kept a mistress for years and that was never discussed publicly.
In the case of Obama, the GOP noted that their top priority was to make him a 1-term president and that meant attempted sabotage of any legislation that might make him look good.
Neither man were perfect presidents, but compared to the current regime it is night and day.
The Lewinsky Affair got traction because Clinton used his position of power (literally in the Oval Office) to take advantage of a young subordinate, in a time when ‘sexual harassment’ was becoming a hot topic. Then lying about the affair made it much worse (as cover-ups often do). It was definitely used against Clinton by his opponents, but the way he abused his position, then perjured himself was truly shameful.