I guess what happens is people can redact it such that they can no longer see it in their particular pdf software but then a different software can bypass it

That's pretty charitable. I've worked civil service many years ago and the computer skills of some of them were beyond laughable. I never dealt with redacted documents during that stint of my life but I can say with 100% certainty that I wouldn't be the least bit surprised if someone "redacted" a document by making the text and background highlight color black and posting the Word docx file online.