Cruelty is the objective, because the America is unwilling to enact the laws that will most effectively stem immigration. These are:

1. Make it illegal to hire undocumented immigrants. 2. Foreign specialists need to earn at least an x% above industry standard (to prove they are specialists).

These laws will obviously not fly among corporate donors. Trump will also never deport all illegals because of how much hospitality and agriculture rely on them. In the end it is all show and spectacle. That's what all the tactical gear is for.