Actually you are getting push back because of your bias of a social issue, you are trying to overlay on real estate.
If we follow your logic, 11% of buyers are smokers, and therefore, are due a discounted price when they buy a home where someone else was a smoker. And, they are due that discount because???? They don't smell what you smell.

Why should smokers get a cheaper home than non-smokers? Because non-smokers think they smell something?
If your property smells of something, it might limit the pool of potential buyers, but might now warrant a discount because a buyer does not have as heightened a sense of smell as you do.
If you are looking at stains that have not been clean, either from smoke, or urine, or anything else, it is just an indication of deferred maintenance, and should be a hint to look for larger maintenance issues. But really, would you expect a moldy home to receive an additional negative adjustment, because you think you detected a smell of smokers too?
The very same thing can be said of pets.
Good agents will ask a potential buyer ahead of time if they are allergic to pets then check the seller's disclosures to see if pets are, or have recently lived in the home. There is nothing worse for an agent, than to take a potential buyer to a home and the buyer breaks out in allergy hives.
yet no negative adjustment is warranted for pets, even if, the buyer starts heaving and can't breath. Because the buyer just won't buy it, no matter what.
Your bias, not ours.
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