That's not my take on what he's been saying. He's upset with investigations like this where there is no underlying crime -- as he says, "collusion" is not a crime, so the investigation is purely political. He doesn't want the justice system weaponized just to punish political enemies.
If someone presented hard evidence that Clinton committed a crime, maybe he'd be opposed, but that would surprise me. But then, we'll never find out, at least not until we have a Republican DoJ, which won't happen until at least Trump's second term -- if he survives that long.
Here you go.