There's a libertarian principle called minimal force. That is to say, libertarians believe that the initiation of force is immoral, and thus use of force against the initiators is just, but only sufficient to mitigate the crime.

When someone steals your laptop, they are initiating force. In doing so, they give you the right to use methods, such as this software, to recover the laptop. But that right only extends to recovering the laptop, not to unnecessarily violate the privacy of the thief. While the thief does owe the laptop owner compensation for the crime, this is something that is determined via court, not by the victim of the crime.

So, yes, you have the right to hack into your laptop, turn on the webcam, collect evidence necessary to locate and recover the laptop, but you don't have the moral right to exploit the thief beyond that.

I remember the Defcon presentation had some privacy obscuring bits for the thief when he took nude shots of himself in the shower. That's appropriate. Shaming the theif by showing their face is reasonable, but only if you know they aren't an accidental victim. Sharing the thief's nude photos with the police or with any unnecessary third parties, where the they are not necessary for recovery, is a violation of privacy.

At least morally. Who knows whether a government in the US will hold the police accountable for any immoral actions.