Absence of evidence is not evidence of absence.
Correct. Not more, not less. Question is what the default assumption is. With enough BS thrown around, the public seems to tend to tilt to "something is fishy" without any (non-debunked) evidence having ever been presented. Doesn't mean it never will be, but until then, a lot of debunked falsehoods shouldn't create more bias than just silence. Sadly, something always sticks.