Not my field, but consider law as a codification of custom. If a community practices "nonsensical disclaimers", adapts that practice to stakeholder concerns, establishes that practice as socially viable and worthwhile, and proliferates it as custom, then I suggest that yes, the law may well change.

Even in the short term, "nonsensical disclaimers" might impact 5-factor fair use decisions.

And consider the scientific community. Massive ignorance of, and disregard for, the letter of copyright law. There is instead a different social norm, built on acknowledgement. Are those "nonsensical disclaimers"?

Even when creation of law is corrupt, and especially when enforcement of law is corrupt, societal norms do matter.

Perhaps one might usefully examine the youtube copying and "nonsensical disclaimers" as a semi-aware form of civil disobedience?