They should be, however a company building and marketing a harmful product is a separate issue from cops using specious evidence to arrest a man.
Cops (QI aside), are responsible for the actions they take. They shouldn't be able to hide behind "the tools we use are bad", especially when (as a parent poster said), the tool is known to be bad in the first place and the cops still used it.
But literally no one in this thread is arguing to not hold them responsible.
Everyone agrees that yes, the cops and PD are responsible. It's just that some people are arguing that there are other parties that also bear responsibility.
No one thinks the cops should be able to hide behind the fact that the tool is bad. I think these cops should be fired, sued for a wrongful arrest. I think QI should be abolished so wronged party can go after the house of the officer that made the arrest in a civil court. I think the department should be on the hook for a large settlement payment.
But I also think the criminal justice system should enjoin future departments from using this known bad technology. I think we should also be mad at the technology vendors that created this bad tool.