Remember that this isn't really a ripe area for police abusing their powers. It's not like they are out ticketing jaywalkers while someone is getting mugged in the next alley. In this case the police are in the alley, luring the muggers to them. Others will get caught in the trap as well but they are collateral damage. That's unfortunate, but seems acceptable when looking at the perps who got caught here.
There was a problem with how evidence was handled. I don't remember the details, but I think the police lied to get their victims. A separate trial was held for that, but again, I don't know the details. The police alluring others to them is the problem. And I believe it's a big problem. They should be protecting our children and the internet, but "collateral damage" as you call it could become an enormous problem.