Ah. So now liberals believe that the "seriousness" of the charge is the deciding factor.

Yes! Why do say "now"? Many liberals have always felt that the problem with federal immigration law enforcement is that it does not distinguish between people who are genuine dangers to their community and people that are generally law-abiding and pose no threat.

Most of the people who are in those "jail hallways" are either: i) not going to be charged; ii) are there for misdemeanor offenses like drug possession or minor property crimes. 70-80% of arrests are for misdemeanors - fewer than 5% are for serious violent crimes. That was even more true back when sanctuary laws were being first put on the books in most of these places, and drug possession charges made up a large proportion of arrests.

I guess vehicular homicide doesn't meet the bar for "serious"?

Of course it does. The issue isn't whether there exist the 5% of people that are arrested for serious violent crimes; the issue is whether the other 95% deserve to have the same treatment as the 5%.

I mean - do you think that someone who got picked up for a drunk and disorderly, or minor drug possession, deserves to have the same consequences as the guy who killed someone? That it's the just outcome for that guy's kids to grow up without a father, or his wife to have to raise them without a husband, for some minor misdemeanor charges (that would likely get dropped)?

The issue isn't over making the truly bad get major consequences. It's about whether those same major consequences get imposed indiscriminately on the people who are genuinely not truly bad.