I don't really think anyone is disputing that the government is able to change their approach to immigration (though it's telling they're doing it by just freezing appointments rather than passing a law), but that you can make changes to immigration law in a way that respects immigrants as human beings. The government is just choosing not to.

Responding to "it's cruel" with "they're allowed to do it" is kind of sidestepping the core of the complaint.