There are significant safety risks for many other occupations -- truck drivers, construction workers, security guards, even fast food workers. These are not as controversial because the pay is time-based not output-based, and it's easier to unionize and access some level of benefits. All of these occupations are reasonable and available options for nearly any gig worker, and they should be, especially if those aspects are important to someone.
Gig working is an alternative to any of these occupations which have existed for decades -- one that is arguably less dangerous and, more importantly, enables output-based compensation and completely flexible work hours. It's a mostly-unprecedented career option, and it's net new (i.e. there's no evidence that other job opportunities, other than being a taxi driver, of course, have decreased), so no one is forced to pursue it. For those that do, there is major upside, but there are also a few risks. Most notably, the risk of "performing poorly", choosing poor hours/locations and not making enough money, and the very low risk of a safety incident like this unfortunate carjacking.
Uber was generous to cover Morrow's costs in full, it can't be expected to go beyond that for any incident that happens. Those are the risks of the job. And Uber is absolutely well within its rights to ask for an NDA and non-disparagement in exchange. This is standard, whether you accept severance from a job, are raped in an Airbnb, etc. And it's certainly a hell of a lot better than you'd get as a taxi driver.