It may be an unpopular opinion, but I'm kind of fine with that. I mean, Google tracks everybody anyway, but there is no benefit to the society at large. But if in this way you can somehow help preventing mass murder, at least for once this tracking is put to good use. I imagine they must have a lot of false positives so probably concentrate on the worst offenders. If someone is searching for a lot of sick stuff on ways to kill people, maybe a friendly visit with a psychologist could help prevent a tragedy.