You hit the nail on the head. People often jump to reactions without looking at bigger picture.
It is entirely likely that Uber engineers evaluated this scenario, and (correctly) decided that it was safer overall to turn off reactionary breaking - and have that function performed by a human in the driver seat. If they hadn't, these cars might instead have been brake-checking people at 100x the rate.
It's easy to say things like "Uber should have waited until better safety features were available", such as the eye tracking suggestions mentioned elsewhere in this thread. But features like that take time - especially if they're development-only features that would have no place in the final product. Every additional safety feature pushes FSD deployment back.
Globally, 1.25 million people die from car accidents annually. That's over 3,000 people per day. For every day that you delay mass adoption of FSD, you are accruing massive amounts of fatalities that could have been avoided.
FSD does not have to be perfect, it's development will cost innocent lives - but if you're optimizing for minimal loss of life, it's the correct thing to do. Reactionary policies do the opposite of what you intend them to do - they cost more lives in the long run.