Just because something terrible happens to someone in your family does not give you the excuse to be an extremist or to back an extremist who could damage the country.
I get this to a point. I get this when you apply it to the victims of drunk drivers or sex offenders, and, especially when the victim dies, their families. Their pain is immense, but I won't sign off on the sentiment that it's OK to shoot the defendant as he/she comes into court, and I won't sign off on lowering the standard of a criminal trial to something less than "guilt beyond a reasonable doubt" for conviction.
But the Angel Moms are different. THEIR loved ones are dead because their government failed to enforce existing laws. Indeed, those whose loved ones died as a result of Sanctuary Cities can, arguably, say that their loved ones died because their local officials obstructed what should have been the normal workings of the criminal justice system.
Whatever you want to say about Trump's policy, his positions on enforcement reflects existing laws; even "the wall" (which, I admit, may never be built) is consistent as a tool to enforce existing law. Hillary's REAL position is on ignoring existing law until the situation reaches critical mass and some sort of "amnesty" gains sufficient traction. There is a problem with any nation that comes to the point where it cannot be counted on to enforce its own laws. At some point, that nation ceases becoming a government of laws and becomes a government of men. Is that a good thing? Not in my opinion, but that's what Hillary Clinton is actually advocating. (That begs other questions, but that's for other topics.)