This is like saying I can slip malware into a project and so long as the user is the one who executed the code I'm free and clear.. which we both know isn't true.
Say I lay a log on a road which you can clearly see and avoid but choose to drive over and crash your car, that’s prompt injection.
One is way worse than the other.
The prosecution wouldn't even blink if you pointed this out.
Unless the perpetrator intended for that to be the effect.
Have you heard about mens rea?
It turns random logging into laying logs onto a road intending to harm someone with the foreknowledge that they will harm the target and as a consequence any other people traveling on that road.
Terrorism charges and straight to gitmo.
Is writing a prompt in your blog any different from laying a hunting trap on your own property and catching someone's pet? Are you liable for the pet wandering on your property?
Start laying hazards in the middle of the road and see how quickly the police introduce you to things like “reckless endangerment” and “involuntary manslaughter”. The general social contract is that you don’t take actions with the intent of causing harm to others regardless of whether the victim could have avoided the harm had they taken different actions.