DHS/ICE is in a weird constitutional spot. Most immigration violations in the US are _civil_ violations. So the Fourth Amendment is less applicable. It's also why detained immigrants don't automatically get the right to be represented by a lawyer.
ICE/DHS technically are just acting as marshals, merely ensuring that defendants appear at court proceedings and then enforcing court decisions (deportations).
They're actually abducting people from court proceedings (and other scheduled official proceedings) and violating court decisions.
It's not really that the 4th amendment is less applicable, it's that the procedural protections are lower in civil proceedings.
I think it's a pretty big undersell to describe ICE as "marshals" too - they've got plenty of discretion in how they prioritize targeted people and who they detain. They are not just a neutral party executing court orders.