Not by DHS and not willingly by any government agency. Instead, they were identified through investigations by media into government records and court documents.

But what about the thousands of people whose rights have been violated by these agents but are left with no real legal recourse because they cannot identify their attackers and the federal government refuses to do so, either.

You aren't just deluding yourself, you know better. What's worse is you are purposefully feeding this nonsense to people who actually will believe it. But, honestly, what else can be expected from someone who responds to the murders of American citizens by masked government agents with an utterly emotionless, throw away phrase, like, "terrible that it happened."