An aside - it's been mentioned many times in recent years that the rules regarding email for adminstration officials were never so clearly defined as to preclude someone from running their own email server and the Bush administration employed many non governmental email accounts and servers. They even 'lost' Up To 22 million. https://en.wikipedia.org/wiki/Bush_White_House_email_controv...
I'm honestly curious as to why that was never investigated with the same level of intensity.
The simplest explanation is that the Democrats were only briefly in power in Congress and going after the Bush administration didn't make political sense — Obama rather famously called to move forward rather than fight over the past.
In contrast, a wide range of right-wing people have spent three decades and many millions of dollars going after both Clintons, with considerable personal demonization over that time. When Obama was elected, the GOP's goal was to limit him to one term. That means a bunch of people had angles to exploit anything remotely plausible: it kept the base riled up and voting accordingly, it helped attack the sitting president by association, and maybe damage his most likely successor. The entire email story was only discovered as part of the endless attempts to trump up a scandal from the Benghazi attack, by which time the pattern of relentlessly litigating everything was just the assumed default.
There just isn't an equivalent on the Democratic side. Yes, there are people who don't like Bush (or now Trump) but there aren't rich people pushing to scrutinize his private life and the members of Congress don't seem to think that's a good use of their time.
