......if you say e-cigarettes
are harmful and smokers avoid them because of that, you have in fact failed to protect smokers.
All risks occur in a larger context.
I sit at my terminal and type encouraging obesity, muscle degeneration and carpal tunnel syndrome. I decide to exercise instead and encourage muscle injury and possible long term disability. I drive to see a movie with a friend and risk an accident or stay at home watching a dvd and face social isolation which has its own risks. Perhaps an increase in my drinking.
Life is a balancing act with few absolutes. Knowing relative risks is a lot more useful than how harmful some behavior or substance might be in isolation. Because, being alive is all about doing things, its all about accumulating risks.