I'm not sure this is simply a case of Democrats deciding that they don't want to defend the Clintons and they're basically throwing them under the bus. I don't have any insider info that would prove otherwise, but here's another story from today that seems relevant:
After Republicans push Clintons to testify on Epstein, Democrats warn they'll haul in Trump
(NBC News) WASHINGTON Facing the threat of being held in contempt of Congress, Bill and Hillary Clinton agreed Tuesday to testify before the House Oversight Committee about convicted sex offender Jeffrey Epstein.
Democrats now say Republicans have established a precedent when it comes to Congress ability to subpoena and haul in past presidents, first ladies and family members under threat of criminal charges if they refuse a precedent they warn the GOP and Oversight Chairman James Comer, R-Ky., will soon regret.
"We are absolutely going to have Donald Trump testify under oath" when Democrats take back power, California Rep. Ted Lieu, a member of Democratic leadership who for years has been highlighting Donald Trump's ties to Epstein, told NBC News on Tuesday.
https://democraticunderground.com/1016422730
It seems to me that the Clintons genuinely feel like they don't have anything to hide here, and that by appearing they are setting a new bar -- they are going to have people, including people in the media, wondering why the Clintons are the only people being forced to do this, when people like Elon Musk (who is literally in the Epstein files begging to come and party on Epstein's pedo island) are not.
Donald Trump was out there yesterday telling reporters to move on from the Epstein files. By forcing the Clintons to testify, House Republicans are ensuring that the Epstein story is going to keep rolling along.