Who said Tor was against the police?
The fact is, in the United States, the FBI and other law enforcement agencies have been known to plant malware, modify hardware, etc., in order to maintain persistent access to machines they wish to monitor. Whether or not you think this is valid in some cases or all cases is really beside the point. The question is whether exit node hardware can be trusted after a search warrant is served and the police are given full and unmonitored access to said hardware. As a matter of due diligence, I'd argue the hardware and OS can no longer be trusted in such cases.