They weren't responding directly to classroom AI use, they were responding to the parent comment making a general claim about moderation - which included moderation of using Tiktok. My immediate thought was "Tiktok is like meth", would you advocate for moderation of meth?

So I agree with the comment. It was appropriately placed and a valid point. Moderation is key for many things, but there are exceptions. Things that are highly addictive and corrosive may be a good category for exceptions. Things that are clearly bad (e.g. murder) are exceptions.

When someone says "life is as simple as x" and the someon else says "hold on its not that simple, what about this exception" that latter rebuttal is valid and constructive.