My reaction from the title: "That's destruction of property, plain and simple."
After Reading the Article: "Well, given the circumstances, deserved."
Maybe don't engage/consume/manufacture CSAM and it won't be a problem.
I would say they should have only deleted the data that was found to be illegal, but if that data was all over the place... I find it hard to sympathize.
Seizing and selling or destroying property used in the commission of a crime is common. It doesn't seem unreasonable to me if the value of the property is in proportion to the severity of the crime, and the owner of the property has been convicted of the crime (i.e. it's not civil asset forfeiture).
Ah, see that's what I thought at first.
But then I thought, no, don't delete it.
Because then you can bust them for possessing CSAM again, just about as soon as you hand it over, if you've a suitably vindictive frame of mind, and you've no reason not to.
Okay, so -- your flip answer is pretty much exactly how the law should not operate?
That's the point of law. To come up with principles that you can follow consistently, regardless of your feelings in the situation.