So back to my original question: why do so many people feel that anything done willful against you, however minor, is inherently worse than a life changing crises which was an accident? Would you really rather lose a limb in a car accident than to be punched, one time, in the face by a person?
Just like even people who post on the MMM forum each have our own splurges and instances of doing 'illogical' things with some of our budgets that bring us joy, but which other MMM posters would consider frivolous - the entire human race is not perfectly logical, as we often blend emotions with our decisions. As a result, few of our actions are based on pure logic, and will sometimes go so far as to end up ignoring the obvious points you make about a history of zero serious assaults/murders/rapes as a result of buying/selling goods, vs perceived safety risks.
They don't focus on the 3,493,094 perfectly safe, incident-free airplane flights, but rather the 3 plane crashes in the past 15 years. Their tunnel vision ignores the massively large numbers of incident-free transactions, and only looks at the sensationalized incident from a prostitute.
However, one thing to say in their defense is that precisely because there are (relatively speaking) quite a few 'bad people' out there who are convicted of various crimes, part of me is surprised that nothing has happened yet to more Craigslist users (or had and hasn't been publicized), just from a numbers perspective. If x% of the people at large have been the victim of a stranger randomly mugging/assaulting/raping them, you would expect at least some small part of that to carryover into Craigslist transactions (unless the criminals are simply too lazy to pursue it, and/or perhaps fear leaving digital fingerprints)
Also, when you consider the 'average woman' and the 'average man', you'd probably agree that in a situation where a bad person is coming after them, if each woman/man has no self defense training, the 'average woman' might fear having more bad things happen to hear compared to the 'average man', regardless of their physical abilities. I've also seen some studies that show women typically take less risks with investments compared to men, and try to carry that over into everyday life. This would make the typical woman less likely to 'take a risk' by looking at the statistical safety analysis of a Craigslist transaction, and instead appeal to the comforting safety of what her emotions need to feel safe and secure....compared to the typical man, who's testosterone may make him feel more at ease in appealing to logic and looking at a very small risk as being very unlikely in certain situations (like trusting a stranger) compared to a typical woman.
One final aspect to consider is the sense of control. You use an example of not being worried about serious injury in a car accident vs the much smaller risk of being punched in the face by a stranger from Craigslist.
While your car could be hit by another person's car, you are in control of your own car's movement, and are able to control a good part of your car's motion, and can mitigate away your accident probability through safe driving habits, while just part of the 'other stuff' (other drivers) is random and out of your control. However, with a stranger from Craigslist, EVERYTHING related to the safety of the situation is, in a sense, 'out of your control', in the sense that no matter what you do, the stranger will either be nice or be a bad person, irregardless of how you conduct yourself.* So I would suggest that the sense of having very little/if any control over the safety of a situation would subconsciously make people more hesitant to feel safe and secure, regardless of statistical probabilities.
*yes, there can be some things that might put you in a more dangerous situation (like answering your front door with just a bath towel wrapped around you vs being fully-clothed......or pulling out your wallet filled with $10,000 in $100 bills, and opening it in front of a Craigslist seller, at 11pm at night, in a dark alley). This assumes you're not that foolish.