I came to ask the exact same thing. According to this article[0] I read the other week, (and according to my admittedly limited understanding of US law) you definitely need probable cause to arrest someone.

Has this right been repealed in the US? Is this not currently the case? If so, are there court decisions that have temporarily repealed these rights? Am I misunderstanding something?

The cynical part of my mind tells me that nothing has changed apart from the police brazenly ignoring the law, but I'd like to understand if I'm missing something in this regard.

[0] https://lawandcrime.com/legal-analysis/two-dhs-officials-app...