> people spend tens of thousand and millions while they are under suspicion (i.e. not cleared of wrongdoing)
You managed to hit the nail on the proverbial head... "not cleared of wrongdoing" means "guilty until proven innocent" and turns the promise of the justice system on its head - spending millions to prove innocence is just a mundane consequence of that perversion.
> So due process doesn't guarantee an innocent person is not inadvertently "dragged though mud".
And, not quite accidentally, it allows to drug anyone though mud regardless of guilt - both purposefully or inadvertently.
I've said this before but the type of argument you use is quite common and it boils down to the following fallacy: If something is already happening somewhere, sometimes - it's the right thing to do everywhere and all the time.
The fact that the government can excuse and routinely do something while getting away with it doesn't mean that the getting away or the action itself are right or justified.
The discussion here is about the compatibility of government's actions with the spirit of the Constitution which doesn't provide an exemption for habituated wrongs.
Authorities have to conduct investigations. Their voters demand that as part of a civilized society those deputized to keep the peace pursue and solve violations to the public order. Since investigators can't consult a magic ball, their investigations will necessarily involve people who are later cleared. One can attempt the ideal, knowing the ideal is not attainable and that reality is messy. It's a balance. It's not perfect. Some innocent people get caught up in the messy parts.