>Are you saying this was already happening, just as much, under Obama, say?
Are you saying that only this particular type of government abuse matters, so if prior governments didn't do this particular thing, then they're A-OK no matter whatever else they did?
As for your strawman:
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According to Department of Homeland Security (DHS) data from fiscal years 2009 to 2016, more than 3 million individuals were formally removed from the country during the Obama administration. Annually, between 58% and 84% of these removals were so-called "summary removals" carried out through legal procedures such as "expedited removal" and "reinstatement of removal," which do not involve a hearing before an immigration judge. On average, about 74% of removals during this period fell into these categories. https://www.snopes.com/fact-check/obama-deportations-court/
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No police intervened for those 3 million people either (except to deport them summarily).
But the guys that took them didn't wear masks (maybe), so that's ok.
Yes, due process is important. Habeus corpus is important. Rule of law is a cornerstone of democracy. People acting for the state, such as border police, should act lawfully; they should identify themselves, wear the proper uniform, get the proper warrants and so on.
Why? Because you're breaching innocent peoples rights and removing their ability to get justice.
The fact that prior administrations did this on a large scale without the need to have gangs of thugs shows that the lawlessness of the administration is unnecessary to meet the ends of managing immigration.
Could you explain why you consider this a strawman? It sounds like you're onboard with the dismantling of USA democracy?