Don't care. If the illegals or their victims choose to avoid law enforcement for that reason, then that is on them.

You don't have to care, but the people who runs these cities do. Especially since the consequences of lack of cooperation with law enforcement aren't limited just to the "illegals or their victims." Everyone's worse off if law enforcement is less able to do their job.

You were struggling to think of a reason why communities choose to be sanctuary cities (or states). This is one of the main ones. If a large portion of the population isn't here legally, and you drive them underground away from legitimate law enforcement, everyone's less safe.

And in no way does that avoidance justify concealing criminals aliens in our country forever if I read you correctly.

As was pointed out upthread, you don't read me correctly. Sanctuary city policies don't involve concealing criminal aliens - they typically involve local government refusing to undertake any voluntary efforts to help ICE across the board. Many (most?) sanctuary policies will draw a line somewhere between helping ICE deport people who have been convicted of serious crimes and avoiding having someone deported when they're pulled over for a traffic violation, to give the two extremes.

I'm not trying to convince you of this perspective, but there are many people who don't think it's a just outcome for someone to get deported if they've spent decades living here as an upright member of the community, working hard and raising a family and just trying to live their life. That's not a popular position at this very moment, but historically Americans have generally favored a "path to citizenship" for such longtime residents rather than mass deportation.

I get that's not your perspective....but there's a reason why Javert was not the hero of Les Mis. Showing forbearance to someone who's lived a good life, despite an early violation of the law, is a popular position. It's not your position (or LM or Dope), and I understand where you're coming from. But there's a fair number of people who disagree with you that the best thing to do with an undocumented person who's lived here for decades and shown themselves to be a decent person just trying to lead a better life is to deport them.