Imprisonment until when? Because at some point you’d have to let them out, and then you’re back to square one. Crossing a border to seek a better life isn’t a crime worthy of lifetime imprisonment.
They won’t give them a path to citizenship because of xenophobia, plain and simple. Immigration is good for the economy, and there’s no such thing as “stealing jobs”, so it only comes down to wanting to maintain cultural (or ethnic) purity.
As was established earlier in the comment chain, conservatives are openly allied with Nazis now.
A Nazi did the Nazi salute in front of every conservative in America, and not one of them repudiated him. So don’t play dumb.