Every one of those agencies has had, in their history, at least some cases of individual abuse (e.g. one particular individual abusing their power). This is unavoidable (because these agencies employ humans, and humans are assholes sometimes) but as long as the situation is appropriately handled at the organizational level (the responsible party is reprimanded in an appropriate way, e.g. let go, tried, ... and practices and protocols are put into place to deal with and prevent these kind of situations) this is OK, because the agency operating is still a net win for humanity.
Most people who are paranoid about these kind of things are so because the media loves to pick up these stories and hype them up and spread fear -- but I don't think it's that much of a problem.
The thing that's really a worry (and that media usually does not report on) is when abuse happens in a systemic fashion, e.g. agencies bending the interpretation of the law to extend their reach. Incidentally, this is exactly what palantirs software is designed to help with, because it can actually enforce these rules.