The arsons are a small blip in a country of 300 million+ people, not a national threat. This presidential concentration-camp tweet is an unhinged response no matter how you slice it.
Punishment's main goal is to discourage the behavior. If old one doesn't cut it anymore they usually make it worse, no matter the times we live in, or subject. That's how it goes, anything to stop bad behavior.
Saying this as an outsider, not even from the US.