No, it is not. But given the abysmal lack of technical knowledge of the "typical computer user" they don't see the redacted PDF's as "having black stick-it not

No, it is not. But given the abysmal lack of technical knowledge of the "typical computer user" they don't see the redacted PDF's as "having black stick-it notes stuck on top of the text". They see the PDF as having had a "black marker pen" applied that has obliterated the text from view. When someone then shows them how to copy/paste out the original text, because the PDF was simply black stick-it notes above the text, it appears to them as if that someone is a magical wizard of infinite intelligence.