If the expected value of (the cost of defending vs the accusation + the cost of losing the defense) is sufficiently greater than $100, it makes sense to pay the $100.
IANAL. In this context, possibly not. However, in US courts, culpability is a major consideration in many types of civil litigation. Lawsuits concerning malpractice, contract violations, torturous interference, defamation, wrongful death, etc. go beyond merely mediating a dispute.
No, actually, they don't.
Really.
In all of the things you list, the main damages are viewed as monetary, and the expected relief is monetary.
This is actually what gets so many people upset - people see it as, like, "they killed my son" and the civil court's #1 job is literally to figure out "how much should someone pay for killing your son".
That is a mismatch for how people often feel about it (they really want the court to help prevent it from happening, etc), but for the most part, civil courts can't do that effectively It's a little more nuanced than that, since there are "punitive damages" and such, but as far as mechanisms to improve society go, it's not necessarily the right hammer for all the nails.
So like I said, there is a small amount of injunctive relief/etc, but the vast majority of civil litigation has a monetary outcome.
If you are interested, it may be worth reading some of the history of how these systems came about - the transformation from two people walking in front of the king and asking him to settle their issue, to what we have now.
