An obvious example is Renée Good, whose Fourth and Fifth Amendment rights (among others) the federal government (through ICE) and Jonathan Ross egregiously and publicly violated, in my view.
Also, non-citizens also enjoy a subset of federal Constitutional and statutory rights, as well as other rights under state and local laws.
And let's remember that we're talking about fellow human beings, not impersonal "illegals".
"Sanctuary cities" merely don't have local law enforcement do the federal job of immigration enforcement. There are reasons for this, mainly that it keeps the mechanics of the legal system going. Everyone can participate without fear of getting deported.
You're just repeating Trumpist propaganda.