Actually, this was the general policy of police in California for decades, including LA.
You couldn’t have a city like LA with a million illegals who were afraid to talk to the police. (It would create a subculture controlled by criminals.) Nor, could you have a city where a million people would never be willing to appear as witnesses (even if, say, they witnessed you in a car crash).
Immigration was considered a federal problem.
Those reasons are still valid; if you haven’t kept the illegals out, you’re going to have to adjust to their presence.
(That said, we should be able to control our borders; or else just put up a sign, “Come and get it!”)
“As long as you reside in our community, our mission is to keep you safe. Nothing else is important to us.”
That’s obvious...you certainly don’t take your oath to protect your cities CITIZENS seriously!