Earlier quoted context omitted.
I agree that it's a ridiculous hypothetical and any company shipping something like that should also face punishment.
Only the company shipping that should face punishment. Their code instructed a machine to kill people, etc. The hypothetical t-shirt is data, not code. These are very important distinctions. Code needs to be responsible for its data. I’d even argue that to be used on public road that any self driving code needs to be open source.
It is data you are intentionally using to hurt someone. If a person legally gained access to a water treatment plant and sent inputs to poison the water, you wouldn't say that person only sent data and the code was at fault. The shirt is inputting data into the car the same way.
Tools should be made with safety in mind, but when people use them to cause harm the person is at fault too.