Like most internet meme phrases, this is both trite and inaccurate. The cruelty is not the point. This administration has decided foreigners are the scapegoat, and wants to get rid of as many as they can. It’s heartless, but cruelty is not the objective.
The ultimate goal might be some political aim and in that sense cruelty is not the ultimate point but what is usually meant by this phrase is that the cruelty is not an unintentional oversight, an unintentional side effect. It is intentional (and there to achieve the ultimate political goal).
Normally I’d agree. For this admin the cruelty does actually look intentional as a deterrent. Making it intentionally turbulent to discourage people from trying in the first place.
Yes cruelty is the point for this admin and its voters. They think it makes them more manly looking. They openly brag about it. They glee in it. They go out of their way to endanger goals just to be cruel.
All of that is in the open, if you listen to what they say and watch what they do.
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.