This framing drives me nuts. It's the same claim the CDC makes on their website:
> There is no safe level of smoking.
> Each cigarette you smoke damages your lungs, your blood vessels, and cells throughout your body. Even occasional smoking is harmful, and the best option for any smoker is to quit completely. The more years you smoke, the more you damage your body. Quitting at any age has benefits.
Source: https://www.cdc.gov/vitalsigns/adultsmoking/index.html
First of all, it's absurd. If you smoke, let's just say, I dunno, one puff off a cigarette once a year I am certain there is no measurable health effect. So the claim is wrong.
But more important, this kind of argument could be applied to all kinds of things. In a technical sense, there is no safe amount of air travel, for example. You are exposed to background radiation at measurably higher levels every time you fly and this has measurable impacts on longterm health (pilots and other flight staff have measurably higher rates of cancer). But does the CDC say, "there's no safe amount of air travel?" Do they point out that every flight does some amount of damage to the cells in your body? Do they warn you that the more you do it, the more harmful it is? Do they tell you that quitting is the only way to be sure you're doing no damage?
No! They give actual figures, explain that the risk of infrequent exposure is relatively low, and then provide a simple point of reference to help the public contextualize the risk:
> We are exposed to low levels of radiation when we fly. You would be exposed to about 0.035 mSv (3.5 mrem) of cosmic radiation if you were to fly within the United States from the east coast to the west coast. This amount of radiation is less than the amount of radiation we receive from one chest x-ray.