Just to add to your repertoire, the counter to the "Obama built the cages for kids" is the indiscriminate uniform policy of family separations came about because of Trump’s “zero tolerance” enforcement policy. Obama's policy was to separate kids only if 1) there was a determination the child's safety appeared at risk, or 2) the child was suspected of being directly involved in criminal activity, such as drug smuggling.

Not that nuance will likely help change any Trumper's mind, but presenting facts and injecting them into the middle of their gaslighting, lies and distortions is a form of inoculation. Someone more undecided might come across the exchange and be influenced without you realizing it. I personally don't like leaving the proverbial battlefield to the enemy.