Anything connected with ICE or CBP is a facility that's planned to be used, if they can get away with it, by a modern-day Gestapo to enforce anything Trump wants without question. They already did that a little bit during the last administration, having CBP come in blacked-out uniforms and anonymously snatch people from protests and take them away.
I am thoroughly in favor of them putting up a stink and refusing to let them do any kind of construction for it, anywhere they have the power to stop it.