Under Obama:

If you commit a crime while having entered the country, you are charged in criminal court, meaning you are put in jail awaiting trial. Your kids can't be put in jail with you, thus they are taken care of separately.

If you don't commit a crime, you are charged in civil court and not put in jail awaiting trial, so your kids aren't taken from you.

Under Trump:

Charge everyone in criminal court [0], take away everyone's kids, despite evidence that it doesn't deter [1], because we are evil vindictive (inferred from facts) [expletive] (assumed).

[0] https://www.pewresearch.org/fact-tank/2019/09/27/far-more-im...

[1] https://www.washingtonpost.com/world/national-security/borde...

> I'm sure you've heard this before, but Obama built the cages.

I'm sure you've heard this before, but Obama implemented policies to limit the necessity for their use, while the Trump Administration deliberately maximized their use.