In 1986-87 President Ronald Reagan signed legislation granting amnesty to millions of law-abiding non-citizens who had entered the country illegally before 1982. Reagan and the Congress recognized just how vital these tax-paying workers are to the U.S. economy.

https://en.wikipedia.org/wiki/Immigration_Reform_and_Control_Act_of_1986

The important issue isn't the number of detention centers. It's who's being taken there, how, why, with what due process, and where they're being deported to afterward. The administration has opened all these issues t question.

As for the "worst of the worst," suspected felons have been arrested, convicted, and deported all along as a matter of routine law enforcement.

What's changed since 1987?