We have masked men grabbing people off the streets with no accountability. Perhaps you should be asking for evidence of lack of human rights abuse.
Any non-citizens grabbed (very few! shockingly low false-positive rate, given 300k+ deportations) have been promptly let go.
We could have had a more formal process if the borders weren't opened to literally millions of illegals, but unfortunately that ship has sailed and this is the only practical way to deal with the problem.