Brexit v DACA

EU citizens have a Fundamental RIGHT to free movement between member nations.[1] Prior to Brexit, a citizen of Holland could live in the UK or a Citizen of the UK could live in Belgium. You would still have to comply with local registration laws (e.g., Belgium), but they couldn't deport an EU citizen.

Brexit changed that and removed a right guaranteed by Treaties.

With Deferred Action for Childhood Arrivals, DACA, the people in question are "unlawfully present", which means they are non-compliant with immigration procedures. Deferred action:

is a discretionary, limited immigration benefit by DHS. It can be granted to individuals who are in removal proceedings, who have final orders of removal, or who have never been in removal proceedings. Individuals who have deferred action status can apply for employment authorization and are in the U.S. under color of law. However, there is no direct path from deferred action to lawful permanent residence or to citizenship.  And, it can be revoked at any time.

Deferred action doesn't really grant any right or permanent residency status.  In other words, people were still in danger of deportation under DACA. 

I want to add that most nations will deport a non-citizen who is not compliant with immigration procedures.

Deportation in and of itself can create consequences for international travel/movement.
But, there is a big difference between having a right to reside in a nation taken away from you and being deported because you DO NOT HAVE a right to be in the nation.

While it may create a sad tale, most nations do not show the same consideration the US has in trying to normalise people who have been "unlawfully present". There is no right for people to be unlawfully present to become citizens.

It is not racism, it is international law.

Footnotes:
[1] Article 3(2) of the Treaty on European Union (TEU); Article 21 of the Treaty on the Functioning of the European Union (TFEU); Titles IV and V TFEU; Article 45 of the Charter of Fundamental Rights of the European Union.