It's a means of searching public-facing (albeit cloaked) content, not a means of tracking people specifically.
If anything, it's ethically much superior to what the NSA is doing: law enforcement searches for content that is clearly criminal (child pornography, actual terroristic threats, murder-for-hire services), then requests a warrant after showing the content to a judge. That's how the process should work; identify something illegal at the front, identify probable cause, then go in through the back with court approval. These search engines can only find content that is already accessible to other users.
The NSA is already in the back, looking for justification for already being there, then after finding something, lying and saying they went in through the front.
Of course, this software could theoretically be used to search a database of data unethically exfiltrated without a warrant, but that's not what the stated goal is and there doesn't seem to be any evidence of that.
They're using it to search for "human trafficking", by which they seem to mean adult women having sex in exchange for money. Oh, sorry, adult women who describe themselves as "latina" having for money - mustn't forget that part. (Seriously. Look at the pictures in the article.) Minor details like whether the women in question are actually trafficked, or whether they should be deporting them right back into the hands of the people who trafficked them if they are, have never been terribly important to the police in the US. This will be used to hurt vulnerable women.
If anything, it's ethically much superior to what the NSA is doing: law enforcement searches for content that is clearly criminal (child pornography, actual terroristic threats, murder-for-hire services), then requests a warrant after showing the content to a judge. That's how the process should work; identify something illegal at the front, identify probable cause, then go in through the back with court approval. These search engines can only find content that is already accessible to other users.
The NSA is already in the back, looking for justification for already being there, then after finding something, lying and saying they went in through the front.
Of course, this software could theoretically be used to search a database of data unethically exfiltrated without a warrant, but that's not what the stated goal is and there doesn't seem to be any evidence of that.