Okay, I'm coming around to your point that "everything in moderation" is a reasonable generalization.

My gut still says it's easily misinterpreted and can be used as justification to do something that shouldn't be. It has something to do with scope of applicability, but to be fair that's true of my other "good" examples as well (e.g. water boiling at different temperatures / pressures).

My instinctive "hold on a minute" was the assumption "everything in moderation" was not a good generalization when applied to everyone as individuals rather than more broadly/universally.

I suspect others that took issue had a similar misalignment in scope. (Fentanyl in moderation for a drug addict is not sustainable, fentanyl in moderation for a non-addict recovering from surgery, probably good)

I feel like I've stumbled into some philosophy tar pit - questioning the meaning of generalization, moderation, scope, good judgement and "everything"... so I'll just concede for now, despite feeling uneasy about it.