Okay, and when a cursory look at the bomb actually reveals it to be a fisher-price toy, what then?

What is the scenario where a grey blob gets on your phone that sets off CSAM alerts, an investigator looks at it and sees only a grey blob, and then still decides to alert the authorities even though it's just a grey blob, and the authorities still decide to arrest you even though it's just a grey blob, and the DA still decides to prosecute you even though it's just a grey blob, and a jury still decides to convict you, even though it's still just a grey blob?

You're the one who's off in theory-land imagining that every person in the entire justice system is just as stupid as this algorithm is.