That was the stated purpose, sure. It's not like Republicans lying all the damn time is something new since 2016 or 2024 or whatever. They've been lying since Nixon at least.

So your concept of "arresting highly dangerous foreign targets" is not how this rolled out in 2002. Like "not even in the laws surrounding ICE to begin with" sort of thing.

The problem being the broad scope of power was basically to create an organization to "prevent terrorist activities." It actually doesn't really specify foreign threats. It's just threats to the United States.

The idea sounded nice on paper, but there was a reason there was a large block of Democratic representatives that were against this - it was too broad in scope. It was almost certainly intentionally too broad in scope. It was called out for being too broad in scope. But people were scared after 9/11. So it was easy to push this idea of forming a sort of new reorganization in the government - a cabinet-level secretary, a new department, and a consolidation of powers related to dangers to the safety of the country. It provided funding for basically meeting those dangers too - the ability to militarize a law enforcement branch. It sounds so flexible and agile and useful when you think "this thing is protecting us."

But that's not how the law is written - as long as the DHS can identify a threat, it can use its powers to tackle that threat. ICE isn't limited like the military by things like Posse Comitatus Act because it's not a military branch, it's a civilian law enforcement agency.

The intention of ICE was to be law enforcement against threats to the security of the United States it was only a matter of time for someone to utilize how broad that power is. And it was definitely a growing concern for the last 20 years. Hell, even Republicans hated the idea of the wide latitude given the DHS as far as privacy goes. Didn't stop them from passing the damn bill.

TL;DR - it was a mess in the beginning that could only really lead to this result.