It's not just that these incidents have gone pear-shaped - it's also the response when they do. Every time something goes wrong, DHS and the administration circle the wagons, blame the victims, and fabricate accusations to justify their misconduct. There's zero accountability on the part of CBP and ICE - they're ignoring court orders and shutting out any investigations by local authorities, and the DoJ is declining to conduct civil rights reviews of their conduct (despite that previously being standard in these sorts of situations).
The accusations of "evil" and "cruelty" stem directly from statements made by DHS officials, as well as things shared by government social media accounts. Mocking, belittling, and humiliating people - and gloating about it - is pretty cruel by any objective measure, and that's going to color people's perceptions of all of your actions.
You talk about the "mandate" granted to the administration, but the reality is that Trump's approval on immigration issues has been steadily slipping since at least last summer, and rather than addressing the growing disapproval, DHS has doubled and tripled down on its tactics.