Earlier quoted context omitted.
Those are the 𝘄𝗼𝗿𝘀𝘁 possible uses for this. To illustrate lets imagine a really really good system that had a 0% false negative rate¹ , and a 0.000001%² false positive rate. If we were to sample the entire country looking the the FBI's most wanted we would end up with ~3290 matches, 3280 of which are going to be other people³. Considering high value of the individual the chances of harassment or wrongful arrest…
While valid, your criticism is with the actual ability/execution of the technology, not the concept. Imagine we get it to a 100% match or, more realistically, use it in a way that makes more sense than just flagging someone and ruining their life forever (not to mention being biased). Would you still be opposed to the technology? If so, your opposition has nothing to do with the above argument.
Rather than the hypothetical of 'is this ok if we have 100% accuracy', how about 'is 100% accuracy ever likely to be possible?'
If it's not, then the previous question is about as relevant as 'if unicorns existed, would you want one?' (and yes, I would!)